T0b1/wasmtime
1
0
Fork 0
Code Issues Pull Requests Packages Projects Releases Wiki Activity

[wasi-common] Clean up the use of mutable Entry (#1395)

Browse Source 
* Clean up the use of mutable Entry

Until now, several syscalls including `fd_pwrite` etc. were relying on
mutating `&mut Entry` by mutating its inner file handle. This is
unnecessary in almost all cases since all methods mutating `std::fs::File`
in Rust's libstd are also implemented for `&std::fs::File`.

While here, I've also modified `OsHandle` in BSD to include `RefCell<Option<Dir>>`
rather than `Option<Mutex<Dir>>` as was until now. While `RefCell`
could easily be replaced with `RefCell`, since going multithreading
will require a lot of (probably even) conceptual changes to `wasi-common`,
I thought it'd be best not to mix single- with multithreading contexts
and swap all places at once when it comes to it.

I've also had to make some modifications to virtual FS which mainly
swapped mutability for interior mutability in places.

* Use one-liners wherever convenient
This commit is contained in:
Jakub Konka
2020-03-25 14:00:52 +01:00
committed by GitHub
parent 336d9d1ab6
commit 1f6890e070
9 changed files with 81 additions and 110 deletions
Download Patch File Download Diff File Expand all files Collapse all files

58
crates/wasi-common/src/snapshots/wasi_snapshot_preview1.rs
View File

@@ -7,8 +7,8 @@ use crate::{clock, fd, path, poll};
use log::{debug, error, trace};
use std::cell::Ref;
use std::convert::TryInto;
use std::fs::File;
use std::io::{self, Read, Seek, SeekFrom, Write};
use std::ops::DerefMut;
use wiggle_runtime::{GuestBorrows, GuestPtr};
impl<'a> WasiSnapshotPreview1 for WasiCtx {
@@ -124,10 +124,10 @@ impl<'a> WasiSnapshotPreview1 for WasiCtx {
len,
advice
);
let mut entry = self.get_entry_mut(fd)?;
let entry = self.get_entry(fd)?;
let file = entry
.as_descriptor_mut(types::Rights::FD_ADVISE, types::Rights::empty())?
.as_file_mut()?;
.as_descriptor(types::Rights::FD_ADVISE, types::Rights::empty())?
.as_file()?;
match file {
Descriptor::OsHandle(fd) => fd::advise(&fd, advice, offset, len),
Descriptor::VirtualFile(virt) => virt.advise(advice, offset, len),
@@ -361,13 +361,13 @@ impl<'a> WasiSnapshotPreview1 for WasiCtx {
buf.push(io::IoSliceMut::new(slice));
}
let mut entry = self.get_entry_mut(fd)?;
let entry = self.get_entry(fd)?;
let file = entry
.as_descriptor_mut(
.as_descriptor(
types::Rights::FD_READ | types::Rights::FD_SEEK,
types::Rights::empty(),
)?
.as_file_mut()?;
.as_file()?;
if offset > i64::max_value() as u64 {
return Err(Errno::Io);
@@ -375,6 +375,7 @@ impl<'a> WasiSnapshotPreview1 for WasiCtx {
let host_nread = match file {
Descriptor::OsHandle(fd) => {
let mut fd: &File = fd;
let cur_pos = fd.seek(SeekFrom::Current(0))?;
fd.seek(SeekFrom::Start(offset))?;
let nread = fd.read_vectored(&mut buf)?;
@@ -474,13 +475,13 @@ impl<'a> WasiSnapshotPreview1 for WasiCtx {
buf.push(io::IoSlice::new(slice));
}
let mut entry = self.get_entry_mut(fd)?;
let entry = self.get_entry(fd)?;
let file = entry
.as_descriptor_mut(
.as_descriptor(
types::Rights::FD_WRITE | types::Rights::FD_SEEK,
types::Rights::empty(),
)?
.as_file_mut()?;
.as_file()?;
if offset > i64::max_value() as u64 {
return Err(Errno::Io);
@@ -488,6 +489,7 @@ impl<'a> WasiSnapshotPreview1 for WasiCtx {
let host_nwritten = match file {
Descriptor::OsHandle(fd) => {
let mut fd: &File = fd;
let cur_pos = fd.seek(SeekFrom::Current(0))?;
fd.seek(SeekFrom::Start(offset))?;
let nwritten = fd.write_vectored(&buf)?;
@@ -524,10 +526,10 @@ impl<'a> WasiSnapshotPreview1 for WasiCtx {
slices.push(io::IoSliceMut::new(slice));
}
let mut entry = self.get_entry_mut(fd)?;
let entry = self.get_entry(fd)?;
let host_nread =
match entry.as_descriptor_mut(types::Rights::FD_READ, types::Rights::empty())? {
Descriptor::OsHandle(file) => file.read_vectored(&mut slices)?,
match entry.as_descriptor(types::Rights::FD_READ, types::Rights::empty())? {
Descriptor::OsHandle(file) => (file as &File).read_vectored(&mut slices)?,
Descriptor::VirtualFile(virt) => virt.read_vectored(&mut slices)?,
Descriptor::Stdin => io::stdin().read_vectored(&mut slices)?,
_ => return Err(Errno::Badf),
@@ -554,10 +556,10 @@ impl<'a> WasiSnapshotPreview1 for WasiCtx {
cookie,
);
let mut entry = self.get_entry_mut(fd)?;
let entry = self.get_entry(fd)?;
let file = entry
.as_descriptor_mut(types::Rights::FD_READDIR, types::Rights::empty())?
.as_file_mut()?;
.as_descriptor(types::Rights::FD_READDIR, types::Rights::empty())?
.as_file()?;
fn copy_entities<T: Iterator<Item = Result<(types::Dirent, String)>>>(
iter: T,
@@ -643,17 +645,17 @@ impl<'a> WasiSnapshotPreview1 for WasiCtx {
} else {
types::Rights::FD_SEEK | types::Rights::FD_TELL
};
let mut entry = self.get_entry_mut(fd)?;
let entry = self.get_entry(fd)?;
let file = entry
.as_descriptor_mut(rights, types::Rights::empty())?
.as_file_mut()?;
.as_descriptor(rights, types::Rights::empty())?
.as_file()?;
let pos = match whence {
types::Whence::Cur => SeekFrom::Current(offset),
types::Whence::End => SeekFrom::End(offset),
types::Whence::Set => SeekFrom::Start(offset as u64),
};
let host_newoffset = match file {
Descriptor::OsHandle(fd) => fd.seek(pos)?,
Descriptor::OsHandle(fd) => (fd as &File).seek(pos)?,
Descriptor::VirtualFile(virt) => virt.seek(pos)?,
_ => {
unreachable!(
@@ -689,12 +691,12 @@ impl<'a> WasiSnapshotPreview1 for WasiCtx {
fn fd_tell(&self, fd: types::Fd) -> Result<types::Filesize> {
trace!("fd_tell(fd={:?})", fd);
let mut entry = self.get_entry_mut(fd)?;
let entry = self.get_entry(fd)?;
let file = entry
.as_descriptor_mut(types::Rights::FD_TELL, types::Rights::empty())?
.as_file_mut()?;
.as_descriptor(types::Rights::FD_TELL, types::Rights::empty())?
.as_file()?;
let host_offset = match file {
Descriptor::OsHandle(fd) => fd.seek(SeekFrom::Current(0))?,
Descriptor::OsHandle(fd) => (fd as &File).seek(SeekFrom::Current(0))?,
Descriptor::VirtualFile(virt) => virt.seek(SeekFrom::Current(0))?,
_ => {
unreachable!(
@@ -726,15 +728,15 @@ impl<'a> WasiSnapshotPreview1 for WasiCtx {
}
// perform unbuffered writes
let mut entry = self.get_entry_mut(fd)?;
let entry = self.get_entry(fd)?;
let isatty = entry.isatty();
let desc = entry.as_descriptor_mut(types::Rights::FD_WRITE, types::Rights::empty())?;
let desc = entry.as_descriptor(types::Rights::FD_WRITE, types::Rights::empty())?;
let host_nwritten = match desc {
Descriptor::OsHandle(file) => {
if isatty {
SandboxedTTYWriter::new(file.deref_mut()).write_vectored(&slices)?
SandboxedTTYWriter::new(&mut (file as &File)).write_vectored(&slices)?
} else {
file.write_vectored(&slices)?
(file as &File).write_vectored(&slices)?
}
}
Descriptor::VirtualFile(virt) => {