Auto merge of #59619 - alexcrichton:wasi-fs, r=fitzgen

wasi: Implement more of the standard library

This commit fills out more of the `wasm32-unknown-wasi` target's standard library, notably the `std::fs` module and all of its internals. A few tweaks were made along the way to non-`fs` modules, but the last commit contains the bulk of the work which is to wire up all APIs to their equivalent on WASI targets instead of unconditionally returning "unsupported". After this some basic filesystem operations and such should all be working in WASI!

Author: bors

src/libstd/fs.rs

@@ -881,6 +881,10 @@ impl OpenOptions {
     }
 }
 
+impl AsInner<fs_imp::OpenOptions> for OpenOptions {
+    fn as_inner(&self) -> &fs_imp::OpenOptions { &self.0 }
+}
+
 impl AsInnerMut<fs_imp::OpenOptions> for OpenOptions {
     fn as_inner_mut(&mut self) -> &mut fs_imp::OpenOptions { &mut self.0 }
 }
@@ -1104,6 +1108,10 @@ impl AsInner<fs_imp::FileAttr> for Metadata {
     fn as_inner(&self) -> &fs_imp::FileAttr { &self.0 }
 }
 
+impl FromInner<fs_imp::FileAttr> for Metadata {
+    fn from_inner(attr: fs_imp::FileAttr) -> Metadata { Metadata(attr) }
+}
+
 impl Permissions {
     /// Returns `true` if these permissions describe a readonly (unwritable) file.
     ///

src/libstd/sys/redox/fs.rs

@@ -2,14 +2,17 @@ use crate::os::unix::prelude::*;
 
 use crate::ffi::{OsString, OsStr};
 use crate::fmt;
-use crate::io::{self, Error, ErrorKind, SeekFrom};
+use crate::io::{self, Error, SeekFrom};
 use crate::path::{Path, PathBuf};
 use crate::sync::Arc;
 use crate::sys::fd::FileDesc;
 use crate::sys::time::SystemTime;
 use crate::sys::{cvt, syscall};
 use crate::sys_common::{AsInner, FromInner};
 
+pub use crate::sys_common::fs::copy;
+pub use crate::sys_common::fs::remove_dir_all;
+
 pub struct File(FileDesc);
 
 #[derive(Clone)]
@@ -392,27 +395,6 @@ pub fn rmdir(p: &Path) -> io::Result<()> {
     Ok(())
 }
 
-pub fn remove_dir_all(path: &Path) -> io::Result<()> {
-    let filetype = lstat(path)?.file_type();
-    if filetype.is_symlink() {
-        unlink(path)
-    } else {
-        remove_dir_all_recursive(path)
-    }
-}
-
-fn remove_dir_all_recursive(path: &Path) -> io::Result<()> {
-    for child in readdir(path)? {
-        let child = child?;
-        if child.file_type()?.is_dir() {
-            remove_dir_all_recursive(&child.path())?;
-        } else {
-            unlink(&child.path())?;
-        }
-    }
-    rmdir(path)
-}
-
 pub fn readlink(p: &Path) -> io::Result<PathBuf> {
     let fd = cvt(syscall::open(p.to_str().unwrap(),
                                syscall::O_CLOEXEC | syscall::O_SYMLINK | syscall::O_RDONLY))?;
@@ -455,19 +437,3 @@ pub fn canonicalize(p: &Path) -> io::Result<PathBuf> {
     let file = File(FileDesc::new(fd));
     file.path()
 }
-
-pub fn copy(from: &Path, to: &Path) -> io::Result<u64> {
-    use crate::fs::{File, set_permissions};
-    if !from.is_file() {
-        return Err(Error::new(ErrorKind::InvalidInput,
-                              "the source path is not an existing regular file"))
-    }
-
-    let mut reader = File::open(from)?;
-    let mut writer = File::create(to)?;
-    let perm = reader.metadata()?.permissions();
-
-    let ret = io::copy(&mut reader, &mut writer)?;
-    set_permissions(to, perm)?;
-    Ok(ret)
-}

src/libstd/sys/unix/fs.rs

@@ -36,6 +36,8 @@ use libc::{stat as stat64, fstat as fstat64, lstat as lstat64, off_t as off64_t,
               target_os = "fuchsia")))]
 use libc::{readdir_r as readdir64_r};
 
+pub use crate::sys_common::fs::remove_dir_all;
+
 pub struct File(FileDesc);
 
 #[derive(Clone)]
@@ -734,27 +736,6 @@ pub fn rmdir(p: &Path) -> io::Result<()> {
     Ok(())
 }
 
-pub fn remove_dir_all(path: &Path) -> io::Result<()> {
-    let filetype = lstat(path)?.file_type();
-    if filetype.is_symlink() {
-        unlink(path)
-    } else {
-        remove_dir_all_recursive(path)
-    }
-}
-
-fn remove_dir_all_recursive(path: &Path) -> io::Result<()> {
-    for child in readdir(path)? {
-        let child = child?;
-        if child.file_type()?.is_dir() {
-            remove_dir_all_recursive(&child.path())?;
-        } else {
-            unlink(&child.path())?;
-        }
-    }
-    rmdir(path)
-}
-
 pub fn readlink(p: &Path) -> io::Result<PathBuf> {
     let c_path = cstr(p)?;
     let p = c_path.as_ptr();

src/libstd/sys/wasi/args.rs

@@ -1,30 +1,15 @@
-use crate::any::Any;
 use crate::ffi::CStr;
+use crate::io;
+use crate::sys::cvt_wasi;
 use crate::ffi::OsString;
 use crate::marker::PhantomData;
 use crate::os::wasi::ffi::OsStringExt;
-use crate::ptr;
 use crate::vec;
 
-static mut ARGC: isize = 0;
-static mut ARGV: *const *const u8 = ptr::null();
-
-#[cfg(not(target_feature = "atomics"))]
-pub unsafe fn args_lock() -> impl Any {
-    // No need for a lock if we're single-threaded, but this function will need
-    // to get implemented for multi-threaded scenarios
-}
-
-pub unsafe fn init(argc: isize, argv: *const *const u8) {
-    let _guard = args_lock();
-    ARGC = argc;
-    ARGV = argv;
+pub unsafe fn init(_argc: isize, _argv: *const *const u8) {
 }
 
 pub unsafe fn cleanup() {
-    let _guard = args_lock();
-    ARGC = 0;
-    ARGV = ptr::null();
 }
 
 pub struct Args {
@@ -34,18 +19,31 @@ pub struct Args {
 
 /// Returns the command line arguments
 pub fn args() -> Args {
+    maybe_args().unwrap_or_else(|_| {
+        Args {
+            iter: Vec::new().into_iter(),
+            _dont_send_or_sync_me: PhantomData
+        }
+    })
+}
+
+fn maybe_args() -> io::Result<Args> {
     unsafe {
-        let _guard = args_lock();
-        let args = (0..ARGC)
-            .map(|i| {
-                let cstr = CStr::from_ptr(*ARGV.offset(i) as *const libc::c_char);
-                OsStringExt::from_vec(cstr.to_bytes().to_vec())
-            })
+        let (mut argc, mut argv_buf_size) = (0, 0);
+        cvt_wasi(libc::__wasi_args_sizes_get(&mut argc, &mut argv_buf_size))?;
+
+        let mut argc = vec![0 as *mut libc::c_char; argc];
+        let mut argv_buf = vec![0; argv_buf_size];
+        cvt_wasi(libc::__wasi_args_get(argc.as_mut_ptr(), argv_buf.as_mut_ptr()))?;
+
+        let args = argc.into_iter()
+            .map(|ptr| CStr::from_ptr(ptr).to_bytes().to_vec())
+            .map(|bytes| OsString::from_vec(bytes))
             .collect::<Vec<_>>();
-        Args {
+        Ok(Args {
             iter: args.into_iter(),
             _dont_send_or_sync_me: PhantomData,
-        }
+        })
     }
 }
 

src/libstd/sys/wasi/ext/ffi.rs

@@ -2,60 +2,5 @@
 
 #![stable(feature = "rust1", since = "1.0.0")]
 
-use crate::ffi::{OsStr, OsString};
-use crate::mem;
-use crate::sys::os_str::Buf;
-use crate::sys_common::{FromInner, IntoInner, AsInner};
-
-/// WASI-specific extensions to [`OsString`].
-///
-/// [`OsString`]: ../../../../std/ffi/struct.OsString.html
-#[stable(feature = "rust1", since = "1.0.0")]
-pub trait OsStringExt {
-    /// Creates an `OsString` from a byte vector.
-    #[stable(feature = "rust1", since = "1.0.0")]
-    fn from_vec(vec: Vec<u8>) -> Self;
-
-    /// Yields the underlying byte vector of this `OsString`.
-    #[stable(feature = "rust1", since = "1.0.0")]
-    fn into_vec(self) -> Vec<u8>;
-}
-
-#[stable(feature = "rust1", since = "1.0.0")]
-impl OsStringExt for OsString {
-    fn from_vec(vec: Vec<u8>) -> OsString {
-        FromInner::from_inner(Buf { inner: vec })
-    }
-    fn into_vec(self) -> Vec<u8> {
-        self.into_inner().inner
-    }
-}
-
-/// WASI-specific extensions to [`OsStr`].
-///
-/// [`OsStr`]: ../../../../std/ffi/struct.OsStr.html
 #[stable(feature = "rust1", since = "1.0.0")]
-pub trait OsStrExt {
-    #[stable(feature = "rust1", since = "1.0.0")]
-    /// Creates an [`OsStr`] from a byte slice.
-    ///
-    /// [`OsStr`]: ../../../ffi/struct.OsStr.html
-    fn from_bytes(slice: &[u8]) -> &Self;
-
-    /// Gets the underlying byte view of the [`OsStr`] slice.
-    ///
-    /// [`OsStr`]: ../../../ffi/struct.OsStr.html
-    #[stable(feature = "rust1", since = "1.0.0")]
-    fn as_bytes(&self) -> &[u8];
-}
-
-#[stable(feature = "rust1", since = "1.0.0")]
-impl OsStrExt for OsStr {
-    fn from_bytes(slice: &[u8]) -> &OsStr {
-        unsafe { mem::transmute(slice) }
-    }
-    fn as_bytes(&self) -> &[u8] {
-        &self.as_inner().inner
-    }
-}
-
+pub use crate::sys_common::os_str_bytes::*;