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

Virtual file support (#701)

Browse Source 
* Add support for virtual files (eg, not backed by an OS file).

Virtual files are implemented through trait objects, with a default
implementation that tries to behave like on-disk files, but entirely
backed by in-memory structures.

Co-authored-by: Dan Gohman <sunfish@mozilla.com>
This commit is contained in:
iximeow
2020-03-06 11:08:13 -08:00
committed by GitHub
parent 7f7196a655
commit 7e0d9decbf
19 changed files with 1568 additions and 188 deletions
Download Patch File Download Diff File Expand all files Collapse all files

1
crates/wasi-common/src/sys/unix/fdentry_impl.rs
View File

@@ -11,6 +11,7 @@ impl AsRawFd for Descriptor {
fn as_raw_fd(&self) -> RawFd {
match self {
Self::OsHandle(file) => file.as_raw_fd(),
Self::VirtualFile(_) => panic!("virtual files do not have a raw fd"),
Self::Stdin => io::stdin().as_raw_fd(),
Self::Stdout => io::stdout().as_raw_fd(),
Self::Stderr => io::stderr().as_raw_fd(),

24
crates/wasi-common/src/sys/unix/hostcalls_impl/fs.rs
View File

@@ -1,5 +1,6 @@
#![allow(non_camel_case_types)]
#![allow(unused_unsafe)]
use crate::fdentry::Descriptor;
use crate::host::Dirent;
use crate::hostcalls_impl::PathGet;
use crate::sys::{fdentry_impl::OsHandle, host_impl, unix::sys_impl};
@@ -60,16 +61,9 @@ pub(crate) fn fd_advise(
unsafe { posix_fadvise(file.as_raw_fd(), offset, len, host_advice) }.map_err(Into::into)
}
pub(crate) fn path_create_directory(resolved: PathGet) -> Result<()> {
pub(crate) fn path_create_directory(base: &File, path: &str) -> Result<()> {
use yanix::file::{mkdirat, Mode};
unsafe {
mkdirat(
resolved.dirfd().as_raw_fd(),
resolved.path(),
Mode::from_bits_truncate(0o777),
)
}
.map_err(Into::into)
unsafe { mkdirat(base.as_raw_fd(), path, Mode::from_bits_truncate(0o777)) }.map_err(Into::into)
}
pub(crate) fn path_link(resolved_old: PathGet, resolved_new: PathGet) -> Result<()> {
@@ -92,7 +86,7 @@ pub(crate) fn path_open(
write: bool,
oflags: wasi::__wasi_oflags_t,
fs_flags: wasi::__wasi_fdflags_t,
) -> Result<File> {
) -> Result<Descriptor> {
use yanix::file::{fstatat, openat, AtFlag, FileType, Mode, OFlag};
let mut nix_all_oflags = if read && write {
@@ -119,14 +113,15 @@ pub(crate) fn path_open(
log::debug!("path_open resolved = {:?}", resolved);
log::debug!("path_open oflags = {:?}", nix_all_oflags);
let new_fd = match unsafe {
let fd_no = unsafe {
openat(
resolved.dirfd().as_raw_fd(),
resolved.path(),
nix_all_oflags,
Mode::from_bits_truncate(0o666),
)
} {
};
let new_fd = match fd_no {
Ok(fd) => fd,
Err(e) => {
if let yanix::Error::Io(ref err) = e {
@@ -188,7 +183,7 @@ pub(crate) fn path_open(
log::debug!("path_open (host) new_fd = {:?}", new_fd);
// Determine the type of the new file descriptor and which rights contradict with this type
Ok(unsafe { File::from_raw_fd(new_fd) })
Ok(OsHandle::from(unsafe { File::from_raw_fd(new_fd) }).into())
}
pub(crate) fn path_readlink(resolved: PathGet, buf: &mut [u8]) -> Result<usize> {
@@ -263,7 +258,7 @@ pub(crate) fn path_filestat_set_times(
};
utimensat(
resolved.dirfd(),
&resolved.dirfd().as_os_handle(),
resolved.path(),
atim,
mtim,
@@ -274,6 +269,7 @@ pub(crate) fn path_filestat_set_times(
pub(crate) fn path_remove_directory(resolved: PathGet) -> Result<()> {
use yanix::file::{unlinkat, AtFlag};
unsafe {
unlinkat(
resolved.dirfd().as_raw_fd(),

24
crates/wasi-common/src/sys/unix/linux/hostcalls_impl.rs
View File

@@ -1,3 +1,4 @@
use crate::fdentry::Descriptor;
use crate::hostcalls_impl::PathGet;
use crate::Result;
use std::os::unix::prelude::AsRawFd;
@@ -26,15 +27,22 @@ pub(crate) fn path_symlink(old_path: &str, resolved: PathGet) -> Result<()> {
pub(crate) fn path_rename(resolved_old: PathGet, resolved_new: PathGet) -> Result<()> {
use yanix::file::renameat;
unsafe {
renameat(
resolved_old.dirfd().as_raw_fd(),
resolved_old.path(),
resolved_new.dirfd().as_raw_fd(),
resolved_new.path(),
)
match (resolved_old.dirfd(), resolved_new.dirfd()) {
(Descriptor::OsHandle(resolved_old_file), Descriptor::OsHandle(resolved_new_file)) => {
unsafe {
renameat(
resolved_old_file.as_raw_fd(),
resolved_old.path(),
resolved_new_file.as_raw_fd(),
resolved_new.path(),
)
}
.map_err(Into::into)
}
_ => {
unimplemented!("path_link with one or more virtual files");
}
}
.map_err(Into::into)
}
pub(crate) mod fd_readdir_impl {

3
crates/wasi-common/src/sys/windows/fdentry_impl.rs
View File

@@ -39,6 +39,9 @@ impl AsRawHandle for Descriptor {
fn as_raw_handle(&self) -> RawHandle {
match self {
Self::OsHandle(file) => file.as_raw_handle(),
Self::VirtualFile(_file) => {
unimplemented!("virtual as_raw_handle");
}
Self::Stdin => io::stdin().as_raw_handle(),
Self::Stdout => io::stdout().as_raw_handle(),
Self::Stderr => io::stderr().as_raw_handle(),

18
crates/wasi-common/src/sys/windows/hostcalls_impl/fs.rs
View File

@@ -2,7 +2,7 @@
#![allow(unused)]
use super::fs_helpers::*;
use crate::ctx::WasiCtx;
use crate::fdentry::FdEntry;
use crate::fdentry::{Descriptor, FdEntry};
use crate::host::{Dirent, FileType};
use crate::hostcalls_impl::{fd_filestat_set_times_impl, PathGet};
use crate::sys::fdentry_impl::{determine_type_rights, OsHandle};
@@ -119,8 +119,8 @@ pub(crate) fn fd_advise(
Ok(())
}
pub(crate) fn path_create_directory(resolved: PathGet) -> Result<()> {
let path = resolved.concatenate()?;
pub(crate) fn path_create_directory(file: &File, path: &str) -> Result<()> {
let path = concatenate(file, path)?;
std::fs::create_dir(&path).map_err(Into::into)
}
@@ -134,7 +134,7 @@ pub(crate) fn path_open(
write: bool,
oflags: wasi::__wasi_oflags_t,
fdflags: wasi::__wasi_fdflags_t,
) -> Result<File> {
) -> Result<Descriptor> {
use winx::file::{AccessMode, CreationDisposition, Flags};
let is_trunc = oflags & wasi::__WASI_OFLAGS_TRUNC != 0;
@@ -207,6 +207,7 @@ pub(crate) fn path_open(
opts.access_mode(access_mode.bits())
.custom_flags(file_flags_from_fdflags(fdflags).bits())
.open(&path)
.map(|f| OsHandle::from(f).into())
.map_err(Into::into)
}
@@ -371,7 +372,7 @@ pub(crate) fn path_readlink(resolved: PathGet, buf: &mut [u8]) -> Result<usize>
// we need to strip the prefix from the absolute path
// as otherwise we will error out since WASI is not capable
// of dealing with absolute paths
let dir_path = get_file_path(resolved.dirfd())?;
let dir_path = get_file_path(&resolved.dirfd().as_os_handle())?;
let dir_path = PathBuf::from(strip_extended_prefix(dir_path));
let target_path = target_path
.strip_prefix(dir_path)
@@ -401,7 +402,7 @@ pub(crate) fn path_readlink(resolved: PathGet, buf: &mut [u8]) -> Result<usize>
fn strip_trailing_slashes_and_concatenate(resolved: &PathGet) -> Result<Option<PathBuf>> {
if resolved.path().ends_with('/') {
let suffix = resolved.path().trim_end_matches('/');
concatenate(resolved.dirfd(), Path::new(suffix)).map(Some)
concatenate(&resolved.dirfd().as_os_handle(), Path::new(suffix)).map(Some)
} else {
Ok(None)
}
@@ -492,14 +493,15 @@ pub(crate) fn path_filestat_set_times(
let file = OpenOptions::new()
.access_mode(AccessMode::FILE_WRITE_ATTRIBUTES.bits())
.open(path)?;
fd_filestat_set_times_impl(&file, st_atim, st_mtim, fst_flags)
let modifiable_fd = Descriptor::OsHandle(OsHandle::from(file));
fd_filestat_set_times_impl(&modifiable_fd, st_atim, st_mtim, fst_flags)
}
pub(crate) fn path_symlink(old_path: &str, resolved: PathGet) -> Result<()> {
use std::os::windows::fs::{symlink_dir, symlink_file};
use winx::winerror::WinError;
let old_path = concatenate(resolved.dirfd(), Path::new(old_path))?;
let old_path = concatenate(&resolved.dirfd().as_os_handle(), Path::new(old_path))?;
let new_path = resolved.concatenate()?;
// try creating a file symlink

15
crates/wasi-common/src/sys/windows/hostcalls_impl/fs_helpers.rs
View File

@@ -1,4 +1,5 @@
#![allow(non_camel_case_types)]
use crate::fdentry::Descriptor;
use crate::hostcalls_impl::PathGet;
use crate::{wasi, Error, Result};
use std::ffi::{OsStr, OsString};
@@ -12,7 +13,15 @@ pub(crate) trait PathGetExt {
impl PathGetExt for PathGet {
fn concatenate(&self) -> Result<PathBuf> {
concatenate(self.dirfd(), Path::new(self.path()))
match self.dirfd() {
Descriptor::OsHandle(file) => concatenate(file, Path::new(self.path())),
Descriptor::VirtualFile(_virt) => {
panic!("concatenate on a virtual base");
}
Descriptor::Stdin | Descriptor::Stdout | Descriptor::Stderr => {
unreachable!("streams do not have paths and should not be accessible via PathGet");
}
}
}
}
@@ -126,7 +135,7 @@ pub(crate) fn strip_extended_prefix<P: AsRef<OsStr>>(path: P) -> OsString {
}
}
pub(crate) fn concatenate<P: AsRef<Path>>(dirfd: &File, path: P) -> Result<PathBuf> {
pub(crate) fn concatenate<P: AsRef<Path>>(file: &File, path: P) -> Result<PathBuf> {
use winx::file::get_file_path;
// WASI is not able to deal with absolute paths
@@ -135,7 +144,7 @@ pub(crate) fn concatenate<P: AsRef<Path>>(dirfd: &File, path: P) -> Result<PathB
return Err(Error::ENOTCAPABLE);
}
let dir_path = get_file_path(dirfd)?;
let dir_path = get_file_path(file)?;
// concatenate paths
let mut out_path = PathBuf::from(dir_path);
out_path.push(path.as_ref());

6
crates/wasi-common/src/sys/windows/hostcalls_impl/misc.rs
View File

@@ -222,6 +222,9 @@ fn handle_rw_event(event: FdEventData, out_events: &mut Vec<wasi::__wasi_event_t
Descriptor::Stdin => Ok(1),
// On Unix, ioctl(FIONREAD) will return 0 for stdout/stderr. Emulate the same behavior on Windows.
Descriptor::Stdout | Descriptor::Stderr => Ok(0),
Descriptor::VirtualFile(_) => {
panic!("virtual files do not get rw events");
}
};
let new_event = make_rw_event(&event, size);
@@ -295,6 +298,9 @@ pub(crate) fn poll_oneoff(
unreachable!();
}
}
Descriptor::VirtualFile(_) => {
panic!("virtual files do not get rw events");
}
}
}