Reuse errno_from_ioerror to simplify error handling

src/ctx.rs

@@ -1,5 +1,5 @@
 use crate::fdentry::FdEntry;
-use crate::sys::{dev_null, errno_from_host};
+use crate::sys::{dev_null, errno_from_ioerror};
 use crate::{host, Result};
 use std::borrow::Borrow;
 use std::collections::HashMap;
@@ -92,11 +92,7 @@ impl WasiCtxBuilder {
         // startup code starts looking at fd 3 for preopens
         let mut preopen_fd = 3;
         for (guest_path, dir) in self.preopens {
-            if !dir
+            if !dir.metadata().map_err(errno_from_ioerror)?.is_dir() {
-                .metadata()
-                .map_err(|err| err.raw_os_error().map_or(host::__WASI_EIO, errno_from_host))?
-                .is_dir()
-            {
                 return Err(host::__WASI_EBADF);
             }
 

src/fdentry.rs

@@ -1,4 +1,4 @@
-use crate::sys::{errno_from_host, fdentry_impl};
+use crate::sys::{errno_from_ioerror, fdentry_impl};
 use crate::{host, Result};
 
 use std::mem::ManuallyDrop;
@@ -92,7 +92,7 @@ impl FdEntry {
 
     pub fn duplicate(file: &fs::File) -> Result<Self> {
         file.try_clone()
-            .map_err(|err| err.raw_os_error().map_or(host::__WASI_EIO, errno_from_host))
+            .map_err(errno_from_ioerror)
             .and_then(Self::from)
     }
 

src/hostcalls_impl/fs.rs

@@ -5,7 +5,7 @@ use crate::fdentry::{Descriptor, FdEntry};
 use crate::memory::*;
 use crate::sys::fdentry_impl::determine_type_rights;
 use crate::sys::hostcalls_impl::fs_helpers::path_open_rights;
-use crate::sys::{errno_from_host, host_impl, hostcalls_impl};
+use crate::sys::{errno_from_ioerror, host_impl, hostcalls_impl};
 use crate::{host, wasm32, Result};
 use log::trace;
 use std::io::{self, Read, Seek, SeekFrom, Write};
@@ -35,8 +35,7 @@ pub(crate) fn fd_datasync(wasi_ctx: &WasiCtx, fd: wasm32::__wasi_fd_t) -> Result
         .get_fd_entry(fd, host::__WASI_RIGHT_FD_DATASYNC, 0)
         .and_then(|fe| fe.fd_object.descriptor.as_file())?;
 
-    fd.sync_data()
+    fd.sync_data().map_err(errno_from_ioerror)
-        .map_err(|err| err.raw_os_error().map_or(host::__WASI_EIO, errno_from_host))
 }
 
 pub(crate) fn fd_pread(
@@ -161,8 +160,7 @@ pub(crate) fn fd_read(
         _ => return Err(host::__WASI_EBADF),
     };
 
-    let host_nread = maybe_host_nread
+    let host_nread = maybe_host_nread.map_err(errno_from_ioerror)?;
-        .map_err(|err| err.raw_os_error().map_or(host::__WASI_EIO, errno_from_host))?;
 
     trace!("     | *nread={:?}", host_nread);
 
@@ -245,10 +243,7 @@ pub(crate) fn fd_seek(
         host::__WASI_WHENCE_SET => SeekFrom::Start(offset as u64),
         _ => return Err(host::__WASI_EINVAL),
     };
-    let host_newoffset = fd.seek(pos).map_err(|err| {
+    let host_newoffset = fd.seek(pos).map_err(errno_from_ioerror)?;
-        log::debug!("fd_seek error={:?}", err);
-        err.raw_os_error().map_or(host::__WASI_EIO, errno_from_host)
-    })?;
 
     trace!("     | *newoffset={:?}", host_newoffset);
 
@@ -268,9 +263,7 @@ pub(crate) fn fd_tell(
         .get_fd_entry(fd, host::__WASI_RIGHT_FD_TELL, 0)
         .and_then(|fe| fe.fd_object.descriptor.as_file())?;
 
-    let host_offset = fd
+    let host_offset = fd.seek(SeekFrom::Current(0)).map_err(errno_from_ioerror)?;
-        .seek(SeekFrom::Current(0))
-        .map_err(|err| err.raw_os_error().map_or(host::__WASI_EIO, errno_from_host))?;
 
     trace!("     | *newoffset={:?}", host_offset);
 
@@ -352,8 +345,7 @@ pub(crate) fn fd_sync(wasi_ctx: &WasiCtx, fd: wasm32::__wasi_fd_t) -> Result<()>
     let fd = wasi_ctx
         .get_fd_entry(fd, host::__WASI_RIGHT_FD_SYNC, 0)
         .and_then(|fe| fe.fd_object.descriptor.as_file())?;
-    fd.sync_all()
+    fd.sync_all().map_err(errno_from_ioerror)
-        .map_err(|err| err.raw_os_error().map_or(host::__WASI_EIO, errno_from_host))
 }
 
 pub(crate) fn fd_write(
@@ -382,26 +374,20 @@ pub(crate) fn fd_write(
 
     // perform unbuffered writes
     let host_nwritten = match &mut *fe.fd_object.descriptor {
-        Descriptor::File(f) => f
+        Descriptor::File(f) => f.write_vectored(&iovs).map_err(errno_from_ioerror)?,
-            .write_vectored(&iovs)
-            .map_err(|err| err.raw_os_error().map_or(host::__WASI_EIO, errno_from_host))?,
         Descriptor::Stdin => return Err(host::__WASI_EBADF),
         Descriptor::Stdout => {
             // lock for the duration of the scope
             let stdout = io::stdout();
             let mut stdout = stdout.lock();
-            let nwritten = stdout
+            let nwritten = stdout.write_vectored(&iovs).map_err(errno_from_ioerror)?;
-                .write_vectored(&iovs)
+            stdout.flush().map_err(errno_from_ioerror)?;
-                .map_err(|err| err.raw_os_error().map_or(host::__WASI_EIO, errno_from_host))?;
-            stdout
-                .flush()
-                .map_err(|err| err.raw_os_error().map_or(host::__WASI_EIO, errno_from_host))?;
             nwritten
         }
         Descriptor::Stderr => io::stderr()
             .lock()
             .write_vectored(&iovs)
-            .map_err(|err| err.raw_os_error().map_or(host::__WASI_EIO, errno_from_host))?,
+            .map_err(errno_from_ioerror)?,
     };
 
     trace!("     | *nwritten={:?}", host_nwritten);
@@ -450,9 +436,7 @@ pub(crate) fn fd_allocate(
         .get_fd_entry(fd, host::__WASI_RIGHT_FD_ALLOCATE, 0)
         .and_then(|fe| fe.fd_object.descriptor.as_file())?;
 
-    let metadata = fd
+    let metadata = fd.metadata().map_err(errno_from_ioerror)?;
-        .metadata()
-        .map_err(|err| err.raw_os_error().map_or(host::__WASI_EIO, errno_from_host))?;
 
     let current_size = metadata.len();
     let wanted_size = offset.checked_add(len).ok_or(host::__WASI_E2BIG)?;
@@ -461,8 +445,7 @@ pub(crate) fn fd_allocate(
     }
 
     if wanted_size > current_size {
-        fd.set_len(wanted_size)
+        fd.set_len(wanted_size).map_err(errno_from_ioerror)
-            .map_err(|err| err.raw_os_error().map_or(host::__WASI_EIO, errno_from_host))
     } else {
         Ok(())
     }

src/sys/unix/fdentry_impl.rs

@@ -1,5 +1,5 @@
 use crate::fdentry::Descriptor;
-use crate::sys::errno_from_host;
+use crate::sys::{errno_from_host, errno_from_ioerror};
 use crate::{host, Result};
 use std::io;
 use std::os::unix::prelude::{AsRawFd, FileTypeExt, FromRawFd, RawFd};
@@ -53,7 +53,7 @@ pub(crate) fn determine_type_rights<Fd: AsRawFd>(
             std::mem::ManuallyDrop::new(unsafe { std::fs::File::from_raw_fd(fd.as_raw_fd()) });
         let ft = file
             .metadata()
-            .map_err(|err| err.raw_os_error().map_or(host::__WASI_EIO, errno_from_host))?
+            .map_err(errno_from_ioerror)?
             .file_type();
         if ft.is_block_device() {
             (

src/sys/unix/hostcalls_impl/fs.rs

@@ -3,8 +3,8 @@
 use super::fs_helpers::*;
 use crate::helpers::systemtime_to_timestamp;
 use crate::hostcalls_impl::PathGet;
+use crate::sys::errno_from_ioerror;
 use crate::sys::host_impl;
-use crate::sys::{errno_from_host, errno_from_ioerror};
 use crate::{host, wasm32, Result};
 use nix::libc::{self, c_long, c_void, off_t};
 use std::convert::TryInto;
@@ -18,13 +18,11 @@ pub(crate) fn fd_pread(
     buf: &mut [u8],
     offset: host::__wasi_filesize_t,
 ) -> Result<usize> {
-    file.read_at(buf, offset)
+    file.read_at(buf, offset).map_err(errno_from_ioerror)
-        .map_err(|e| e.raw_os_error().map_or(host::__WASI_EIO, errno_from_host))
 }
 
 pub(crate) fn fd_pwrite(file: &File, buf: &[u8], offset: host::__wasi_filesize_t) -> Result<usize> {
-    file.write_at(buf, offset)
+    file.write_at(buf, offset).map_err(errno_from_ioerror)
-        .map_err(|e| e.raw_os_error().map_or(host::__WASI_EIO, errno_from_host))
 }
 
 pub(crate) fn fd_fdstat_get(fd: &File) -> Result<host::__wasi_fdflags_t> {

src/sys/unix/mod.rs

@@ -2,16 +2,15 @@ pub(crate) mod fdentry_impl;
 pub(crate) mod host_impl;
 pub(crate) mod hostcalls_impl;
 
-use crate::sys::errno_from_host;
+use crate::sys::errno_from_ioerror;
-use crate::{host, Result};
+use crate::Result;
 use std::fs::File;
 use std::path::Path;
 
 pub(crate) fn dev_null() -> Result<File> {
-    File::open("/dev/null")
+    File::open("/dev/null").map_err(errno_from_ioerror)
-        .map_err(|err| err.raw_os_error().map_or(host::__WASI_EIO, errno_from_host))
 }
 
 pub fn preopen_dir<P: AsRef<Path>>(path: P) -> Result<File> {
-    File::open(path).map_err(|err| err.raw_os_error().map_or(host::__WASI_EIO, errno_from_host))
+    File::open(path).map_err(errno_from_ioerror)
 }

src/sys/windows/hostcalls_impl/fs.rs

@@ -42,12 +42,12 @@ pub(crate) fn fd_pread(
     offset: host::__wasi_filesize_t,
 ) -> Result<usize> {
     read_at(file, buf, offset)
-        .map_err(|err| err.raw_os_error().map_or(host::__WASI_EIO, errno_from_host))
+        .map_err(errno_from_ioerror)
 }
 
 pub(crate) fn fd_pwrite(file: &File, buf: &[u8], offset: host::__wasi_filesize_t) -> Result<usize> {
     write_at(file, buf, offset)
-        .map_err(|err| err.raw_os_error().map_or(host::__WASI_EIO, errno_from_host))
+        .map_err(errno_from_ioerror)
 }
 
 pub(crate) fn fd_fdstat_get(fd: &File) -> Result<host::__wasi_fdflags_t> {

src/sys/windows/mod.rs

@@ -2,13 +2,13 @@ pub(crate) mod fdentry_impl;
 pub(crate) mod host_impl;
 pub(crate) mod hostcalls_impl;
 
-use crate::sys::errno_from_host;
+use crate::sys::errno_from_ioerror;
-use crate::{host, Result};
+use crate::Result;
 use std::fs::File;
 use std::path::Path;
 
 pub(crate) fn dev_null() -> Result<File> {
-    File::open("NUL").map_err(|err| err.raw_os_error().map_or(host::__WASI_EIO, errno_from_host))
+    File::open("NUL").map_err(errno_from_ioerror)
 }
 
 pub fn preopen_dir<P: AsRef<Path>>(path: P) -> Result<File> {
@@ -25,5 +25,5 @@ pub fn preopen_dir<P: AsRef<Path>>(path: P) -> Result<File> {
         .read(true)
         .attributes(FILE_FLAG_BACKUP_SEMANTICS)
         .open(path)
-        .map_err(|err| err.raw_os_error().map_or(host::__WASI_EIO, errno_from_host))
+        .map_err(errno_from_ioerror)
 }