Fix incorrect fd_readdir behaviour

* when executed twice in a row, need to manually reset the stream
  by calling seekdir with __WASI_DIRCOOKIE_START, if __WASI_DIRCOOKIE_START
  was specified
* fix mapping between d_type and __wasi_filetype_t
* include minor refactor - removes use of wasm32 module on the
  host's side

src/sys/unix/host_impl.rs

@@ -2,7 +2,7 @@
 #![allow(non_camel_case_types)]
 #![allow(non_snake_case)]
 #![allow(dead_code)]
-use crate::{host, memory, wasm32, Result};
+use crate::{host, memory, Result};
 use std::ffi::OsStr;
 use std::os::unix::prelude::OsStrExt;
 
@@ -228,29 +228,54 @@ pub(crate) fn filestat_from_nix(
     })
 }
 
+pub(crate) fn dirent_filetype_from_host(
+    host_entry: &nix::libc::dirent,
+) -> Result<host::__wasi_filetype_t> {
+    match host_entry.d_type {
+        libc::DT_FIFO => Ok(host::__WASI_FILETYPE_UNKNOWN),
+        libc::DT_CHR => Ok(host::__WASI_FILETYPE_CHARACTER_DEVICE),
+        libc::DT_DIR => Ok(host::__WASI_FILETYPE_DIRECTORY),
+        libc::DT_BLK => Ok(host::__WASI_FILETYPE_BLOCK_DEVICE),
+        libc::DT_REG => Ok(host::__WASI_FILETYPE_REGULAR_FILE),
+        libc::DT_LNK => Ok(host::__WASI_FILETYPE_SYMBOLIC_LINK),
+        libc::DT_SOCK => {
+            // TODO how to discriminate between STREAM and DGRAM?
+            // Perhaps, we should create a more general WASI filetype
+            // such as __WASI_FILETYPE_SOCKET, and then it would be
+            // up to the client to check whether it's actually
+            // STREAM or DGRAM?
+            Ok(host::__WASI_FILETYPE_UNKNOWN)
+        }
+        libc::DT_UNKNOWN => Ok(host::__WASI_FILETYPE_UNKNOWN),
+        _ => Err(host::__WASI_EINVAL),
+    }
+}
+
 #[cfg(target_os = "linux")]
-pub(crate) fn dirent_from_host(host_entry: &nix::libc::dirent) -> Result<wasm32::__wasi_dirent_t> {
+pub(crate) fn dirent_from_host(host_entry: &nix::libc::dirent) -> Result<host::__wasi_dirent_t> {
-    let mut entry = unsafe { std::mem::zeroed::<wasm32::__wasi_dirent_t>() };
+    let mut entry = unsafe { std::mem::zeroed::<host::__wasi_dirent_t>() };
     let d_namlen = unsafe { std::ffi::CStr::from_ptr(host_entry.d_name.as_ptr()) }
         .to_bytes()
         .len();
     if d_namlen > u32::max_value() as usize {
         return Err(host::__WASI_EIO);
     }
+    let d_type = dirent_filetype_from_host(host_entry)?;
     entry.d_ino = memory::enc_inode(host_entry.d_ino);
     entry.d_next = memory::enc_dircookie(host_entry.d_off as u64);
     entry.d_namlen = memory::enc_u32(d_namlen as u32);
-    entry.d_type = memory::enc_filetype(host_entry.d_type);
+    entry.d_type = memory::enc_filetype(d_type);
     Ok(entry)
 }
 
 #[cfg(not(target_os = "linux"))]
-pub(crate) fn dirent_from_host(host_entry: &nix::libc::dirent) -> Result<wasm32::__wasi_dirent_t> {
+pub(crate) fn dirent_from_host(host_entry: &nix::libc::dirent) -> Result<host::__wasi_dirent_t> {
-    let mut entry = unsafe { std::mem::zeroed::<wasm32::__wasi_dirent_t>() };
+    let mut entry = unsafe { std::mem::zeroed::<host::__wasi_dirent_t>() };
+    let d_type = dirent_filetype_from_host(host_entry)?;
     entry.d_ino = memory::enc_inode(host_entry.d_ino);
     entry.d_next = memory::enc_dircookie(host_entry.d_seekoff);
     entry.d_namlen = memory::enc_u32(u32::from(host_entry.d_namlen));
-    entry.d_type = memory::enc_filetype(host_entry.d_type);
+    entry.d_type = memory::enc_filetype(d_type);
     Ok(entry)
 }
 

src/sys/unix/hostcalls_impl/fs.rs

@@ -5,7 +5,7 @@ use crate::helpers::systemtime_to_timestamp;
 use crate::hostcalls_impl::PathGet;
 use crate::sys::errno_from_ioerror;
 use crate::sys::host_impl;
-use crate::{host, wasm32, Result};
+use crate::{host, Result};
 use nix::libc::{self, c_long, c_void};
 use std::convert::TryInto;
 use std::ffi::CString;
@@ -213,7 +213,7 @@ pub(crate) fn fd_readdir(
     host_buf: &mut [u8],
     cookie: host::__wasi_dircookie_t,
 ) -> Result<usize> {
-    use libc::{dirent, fdopendir, memcpy, readdir_r, seekdir};
+    use libc::{dirent, fdopendir, memcpy, readdir_r, rewinddir, seekdir};
 
     let host_buf_ptr = host_buf.as_mut_ptr();
     let host_buf_len = host_buf.len();
@@ -221,9 +221,15 @@ pub(crate) fn fd_readdir(
     if dir.is_null() {
         return Err(host_impl::errno_from_nix(nix::errno::Errno::last()));
     }
-    if cookie != wasm32::__WASI_DIRCOOKIE_START {
+
+    if cookie != host::__WASI_DIRCOOKIE_START {
         unsafe { seekdir(dir, cookie as c_long) };
+    } else {
+        // If cookie set to __WASI_DIRCOOKIE_START, rewind the dir ptr
+        // to the start of the stream.
+        unsafe { rewinddir(dir) };
     }
+
     let mut entry_buf = unsafe { std::mem::uninitialized::<dirent>() };
     let mut left = host_buf_len;
     let mut host_buf_offset: usize = 0;
@@ -236,7 +242,7 @@ pub(crate) fn fd_readdir(
         if host_entry.is_null() {
             break;
         }
-        let entry: wasm32::__wasi_dirent_t = host_impl::dirent_from_host(&unsafe { *host_entry })?;
+        let entry: host::__wasi_dirent_t = host_impl::dirent_from_host(&unsafe { *host_entry })?;
         let name_len = entry.d_namlen as usize;
         let required_space = std::mem::size_of_val(&entry) + name_len;
         if required_space > left {
@@ -244,7 +250,7 @@ pub(crate) fn fd_readdir(
         }
         unsafe {
             let ptr = host_buf_ptr.offset(host_buf_offset as isize) as *mut c_void
-                as *mut wasm32::__wasi_dirent_t;
+                as *mut host::__wasi_dirent_t;
             *ptr = entry;
         }
         host_buf_offset += std::mem::size_of_val(&entry);
@@ -344,8 +350,8 @@ pub(crate) fn fd_filestat_get_impl(file: &std::fs::File) -> Result<host::__wasi_
 }
 
 fn filetype(file: &File, metadata: &Metadata) -> Result<host::__wasi_filetype_t> {
-    use std::os::unix::fs::FileTypeExt;
     use nix::sys::socket::{self, SockType};
+    use std::os::unix::fs::FileTypeExt;
     let ftype = metadata.file_type();
     if ftype.is_file() {
         Ok(host::__WASI_FILETYPE_REGULAR_FILE)
@@ -360,8 +366,10 @@ fn filetype(file: &File, metadata: &Metadata) -> Result<host::__wasi_filetype_t>
     } else if ftype.is_fifo() {
         Ok(host::__WASI_FILETYPE_SOCKET_STREAM)
     } else if ftype.is_socket() {
-        match socket::getsockopt(file.as_raw_fd(), socket::sockopt::SockType).map_err(|err|
+        match socket::getsockopt(file.as_raw_fd(), socket::sockopt::SockType)
-            err.as_errno().unwrap()).map_err(host_impl::errno_from_nix)? {
+            .map_err(|err| err.as_errno().unwrap())
+            .map_err(host_impl::errno_from_nix)?
+        {
             SockType::Datagram => Ok(host::__WASI_FILETYPE_SOCKET_DGRAM),
             SockType::Stream => Ok(host::__WASI_FILETYPE_SOCKET_STREAM),
             _ => Ok(host::__WASI_FILETYPE_UNKNOWN),
@@ -425,7 +433,7 @@ pub(crate) fn path_filestat_set_times(
     }
 
     let atflags = match dirflags {
-        wasm32::__WASI_LOOKUP_SYMLINK_FOLLOW => UtimensatFlags::FollowSymlink,
+        host::__WASI_LOOKUP_SYMLINK_FOLLOW => UtimensatFlags::FollowSymlink,
         _ => UtimensatFlags::NoFollowSymlink,
     };