Reorganize wasi-misc-tests. (#575)

* Reorganize wasi-misc-tests.

Move wasi-misc-tests out of wasi-common, to break a dependency cycle;
previously, wasmtime-* depended on wasi-common, but wasi-common
dev-dependended on wasmtime-*.

Now, wasi-common no longer dev-depends on wasmtime-*; instead, the
tests are in their own crate which depends on wasi-common and on
wasmtime-*.

Also, rename wasi-misc-tests to wasi-tests for simplicity.

This also removes the "wasm_tests" feature; it's replaced by the
"test-programs" feature.

* Update the CI script to use the new feature name.

* Update the CI script to use the new feature name in one more place.

* Change a `write!` to a `writeln!`.

crates/test-programs/wasi-tests/src/bin/big_random_buf.rs

@@ -0,0 +1,18 @@
+use wasi::wasi_unstable;
+
+fn test_big_random_buf() {
+    let mut buf = Vec::new();
+    buf.resize(1024, 0);
+    assert!(
+        wasi_unstable::random_get(&mut buf).is_ok(),
+        "calling get_random on a large buffer"
+    );
+    // Chances are pretty good that at least *one* byte will be non-zero in
+    // any meaningful random function producing 1024 u8 values.
+    assert!(buf.iter().any(|x| *x != 0), "random_get returned all zeros");
+}
+
+fn main() {
+    // Run the tests.
+    test_big_random_buf()
+}

crates/test-programs/wasi-tests/src/bin/clock_time_get.rs

@@ -0,0 +1,37 @@
+use more_asserts::assert_le;
+use wasi::wasi_unstable;
+use wasi_tests::wasi_wrappers::wasi_clock_time_get;
+
+unsafe fn test_clock_time_get() {
+    // Test that clock_time_get succeeds. Even in environments where it's not
+    // desirable to expose high-precision timers, it should still succeed.
+    // clock_res_get is where information about precision can be provided.
+    let mut time: wasi_unstable::Timestamp = 0;
+    let status = wasi_clock_time_get(wasi_unstable::CLOCK_MONOTONIC, 1, &mut time);
+    assert_eq!(
+        status,
+        wasi_unstable::raw::__WASI_ESUCCESS,
+        "clock_time_get with a precision of 1"
+    );
+
+    let status = wasi_clock_time_get(wasi_unstable::CLOCK_MONOTONIC, 0, &mut time);
+    assert_eq!(
+        status,
+        wasi_unstable::raw::__WASI_ESUCCESS,
+        "clock_time_get with a precision of 0"
+    );
+    let first_time = time;
+
+    let status = wasi_clock_time_get(wasi_unstable::CLOCK_MONOTONIC, 0, &mut time);
+    assert_eq!(
+        status,
+        wasi_unstable::raw::__WASI_ESUCCESS,
+        "clock_time_get with a precision of 0"
+    );
+    assert_le!(first_time, time, "CLOCK_MONOTONIC should be monotonic");
+}
+
+fn main() {
+    // Run the tests.
+    unsafe { test_clock_time_get() }
+}

crates/test-programs/wasi-tests/src/bin/close_preopen.rs

@@ -0,0 +1,83 @@
+use libc;
+use more_asserts::assert_gt;
+use std::{env, mem, process};
+use wasi::wasi_unstable;
+use wasi_tests::open_scratch_directory;
+use wasi_tests::wasi_wrappers::wasi_fd_fdstat_get;
+
+unsafe fn test_close_preopen(dir_fd: wasi_unstable::Fd) {
+    let pre_fd: wasi_unstable::Fd = (libc::STDERR_FILENO + 1) as wasi_unstable::Fd;
+
+    assert_gt!(dir_fd, pre_fd, "dir_fd number");
+
+    // Try to close a preopened directory handle.
+    assert_eq!(
+        wasi_unstable::fd_close(pre_fd),
+        Err(wasi_unstable::ENOTSUP),
+        "closing a preopened file descriptor",
+    );
+
+    // Try to renumber over a preopened directory handle.
+    assert_eq!(
+        wasi_unstable::fd_renumber(dir_fd, pre_fd),
+        Err(wasi_unstable::ENOTSUP),
+        "renumbering over a preopened file descriptor",
+    );
+
+    // Ensure that dir_fd is still open.
+    let mut dir_fdstat: wasi_unstable::FdStat = mem::zeroed();
+    let mut status = wasi_fd_fdstat_get(dir_fd, &mut dir_fdstat);
+    assert_eq!(
+        status,
+        wasi_unstable::raw::__WASI_ESUCCESS,
+        "calling fd_fdstat on the scratch directory"
+    );
+    assert_eq!(
+        dir_fdstat.fs_filetype,
+        wasi_unstable::FILETYPE_DIRECTORY,
+        "expected the scratch directory to be a directory",
+    );
+
+    // Try to renumber a preopened directory handle.
+    assert_eq!(
+        wasi_unstable::fd_renumber(pre_fd, dir_fd),
+        Err(wasi_unstable::ENOTSUP),
+        "renumbering over a preopened file descriptor",
+    );
+
+    // Ensure that dir_fd is still open.
+    status = wasi_fd_fdstat_get(dir_fd, &mut dir_fdstat);
+    assert_eq!(
+        status,
+        wasi_unstable::raw::__WASI_ESUCCESS,
+        "calling fd_fdstat on the scratch directory"
+    );
+    assert_eq!(
+        dir_fdstat.fs_filetype,
+        wasi_unstable::FILETYPE_DIRECTORY,
+        "expected the scratch directory to be a directory",
+    );
+}
+
+fn main() {
+    let mut args = env::args();
+    let prog = args.next().unwrap();
+    let arg = if let Some(arg) = args.next() {
+        arg
+    } else {
+        eprintln!("usage: {} <scratch directory>", prog);
+        process::exit(1);
+    };
+
+    // Open scratch directory
+    let dir_fd = match open_scratch_directory(&arg) {
+        Ok(dir_fd) => dir_fd,
+        Err(err) => {
+            eprintln!("{}", err);
+            process::exit(1)
+        }
+    };
+
+    // Run the tests.
+    unsafe { test_close_preopen(dir_fd) }
+}

crates/test-programs/wasi-tests/src/bin/dangling_symlink.rs

@@ -0,0 +1,62 @@
+use std::{env, process};
+use wasi::wasi_unstable;
+use wasi_tests::open_scratch_directory;
+use wasi_tests::utils::cleanup_file;
+use wasi_tests::wasi_wrappers::{wasi_path_open, wasi_path_symlink};
+
+unsafe fn test_dangling_symlink(dir_fd: wasi_unstable::Fd) {
+    // First create a dangling symlink.
+    assert!(
+        wasi_path_symlink("target", dir_fd, "symlink").is_ok(),
+        "creating a symlink"
+    );
+
+    // Try to open it as a directory with O_NOFOLLOW.
+    let mut file_fd: wasi_unstable::Fd = wasi_unstable::Fd::max_value() - 1;
+    let status = wasi_path_open(
+        dir_fd,
+        0,
+        "symlink",
+        wasi_unstable::O_DIRECTORY,
+        0,
+        0,
+        0,
+        &mut file_fd,
+    );
+    assert_eq!(
+        status,
+        wasi_unstable::raw::__WASI_ELOOP,
+        "opening a dangling symlink as a directory",
+    );
+    assert_eq!(
+        file_fd,
+        wasi_unstable::Fd::max_value(),
+        "failed open should set the file descriptor to -1",
+    );
+
+    // Clean up.
+    cleanup_file(dir_fd, "symlink");
+}
+
+fn main() {
+    let mut args = env::args();
+    let prog = args.next().unwrap();
+    let arg = if let Some(arg) = args.next() {
+        arg
+    } else {
+        eprintln!("usage: {} <scratch directory>", prog);
+        process::exit(1);
+    };
+
+    // Open scratch directory
+    let dir_fd = match open_scratch_directory(&arg) {
+        Ok(dir_fd) => dir_fd,
+        Err(err) => {
+            eprintln!("{}", err);
+            process::exit(1)
+        }
+    };
+
+    // Run the tests.
+    unsafe { test_dangling_symlink(dir_fd) }
+}

crates/test-programs/wasi-tests/src/bin/directory_seek.rs

@@ -0,0 +1,89 @@
+use more_asserts::assert_gt;
+use std::{env, mem, process};
+use wasi::wasi_unstable;
+use wasi_tests::open_scratch_directory;
+use wasi_tests::utils::{cleanup_dir, close_fd, create_dir};
+use wasi_tests::wasi_wrappers::{wasi_fd_fdstat_get, wasi_fd_seek, wasi_path_open};
+
+unsafe fn test_directory_seek(dir_fd: wasi_unstable::Fd) {
+    // Create a directory in the scratch directory.
+    create_dir(dir_fd, "dir");
+
+    // Open the directory and attempt to request rights for seeking.
+    let mut fd: wasi_unstable::Fd = wasi_unstable::Fd::max_value() - 1;
+    let mut status = wasi_path_open(
+        dir_fd,
+        0,
+        "dir",
+        0,
+        wasi_unstable::RIGHT_FD_SEEK,
+        0,
+        0,
+        &mut fd,
+    );
+    assert_eq!(
+        status,
+        wasi_unstable::raw::__WASI_ESUCCESS,
+        "opening a file"
+    );
+    assert_gt!(
+        fd,
+        libc::STDERR_FILENO as wasi_unstable::Fd,
+        "file descriptor range check",
+    );
+
+    // Attempt to seek.
+    let mut newoffset = 1;
+    status = wasi_fd_seek(fd, 0, wasi_unstable::WHENCE_CUR, &mut newoffset);
+    assert_eq!(
+        status,
+        wasi_unstable::raw::__WASI_ENOTCAPABLE,
+        "seek on a directory"
+    );
+
+    // Check if we obtained the right to seek.
+    let mut fdstat: wasi_unstable::FdStat = mem::zeroed();
+    status = wasi_fd_fdstat_get(fd, &mut fdstat);
+    assert_eq!(
+        status,
+        wasi_unstable::raw::__WASI_ESUCCESS,
+        "calling fd_fdstat on a directory"
+    );
+    assert_eq!(
+        fdstat.fs_filetype,
+        wasi_unstable::FILETYPE_DIRECTORY,
+        "expected the scratch directory to be a directory",
+    );
+    assert_eq!(
+        (fdstat.fs_rights_base & wasi_unstable::RIGHT_FD_SEEK),
+        0,
+        "directory has the seek right",
+    );
+
+    // Clean up.
+    close_fd(fd);
+    cleanup_dir(dir_fd, "dir");
+}
+
+fn main() {
+    let mut args = env::args();
+    let prog = args.next().unwrap();
+    let arg = if let Some(arg) = args.next() {
+        arg
+    } else {
+        eprintln!("usage: {} <scratch directory>", prog);
+        process::exit(1);
+    };
+
+    // Open scratch directory
+    let dir_fd = match open_scratch_directory(&arg) {
+        Ok(dir_fd) => dir_fd,
+        Err(err) => {
+            eprintln!("{}", err);
+            process::exit(1)
+        }
+    };
+
+    // Run the tests.
+    unsafe { test_directory_seek(dir_fd) }
+}

crates/test-programs/wasi-tests/src/bin/fd_advise.rs

@@ -0,0 +1,98 @@
+use libc;
+use more_asserts::assert_gt;
+use std::{env, process};
+use wasi::wasi_unstable;
+use wasi_tests::open_scratch_directory;
+use wasi_tests::utils::{cleanup_file, close_fd};
+use wasi_tests::wasi_wrappers::{wasi_fd_advise, wasi_fd_filestat_get, wasi_path_open};
+
+unsafe fn test_fd_advise(dir_fd: wasi_unstable::Fd) {
+    // Create a file in the scratch directory.
+    let mut file_fd = wasi_unstable::Fd::max_value() - 1;
+    let status = wasi_path_open(
+        dir_fd,
+        0,
+        "file",
+        wasi_unstable::O_CREAT,
+        wasi_unstable::RIGHT_FD_READ | wasi_unstable::RIGHT_FD_WRITE,
+        0,
+        0,
+        &mut file_fd,
+    );
+    assert_eq!(
+        status,
+        wasi_unstable::raw::__WASI_ESUCCESS,
+        "opening a file"
+    );
+    assert_gt!(
+        file_fd,
+        libc::STDERR_FILENO as wasi_unstable::Fd,
+        "file descriptor range check",
+    );
+
+    // Check file size
+    let mut stat = wasi_unstable::FileStat {
+        st_dev: 0,
+        st_ino: 0,
+        st_filetype: 0,
+        st_nlink: 0,
+        st_size: 0,
+        st_atim: 0,
+        st_mtim: 0,
+        st_ctim: 0,
+    };
+    let status = wasi_fd_filestat_get(file_fd, &mut stat);
+    assert_eq!(
+        status,
+        wasi_unstable::raw::__WASI_ESUCCESS,
+        "reading file stats"
+    );
+    assert_eq!(stat.st_size, 0, "file size should be 0");
+
+    // Allocate some size
+    assert!(
+        wasi_unstable::fd_allocate(file_fd, 0, 100).is_ok(),
+        "allocating size"
+    );
+
+    let status = wasi_fd_filestat_get(file_fd, &mut stat);
+    assert_eq!(
+        status,
+        wasi_unstable::raw::__WASI_ESUCCESS,
+        "reading file stats after initial allocation"
+    );
+    assert_eq!(stat.st_size, 100, "file size should be 100");
+
+    // Advise the kernel
+    let status = wasi_fd_advise(file_fd, 10, 50, wasi_unstable::ADVICE_NORMAL);
+    assert_eq!(
+        status,
+        wasi_unstable::raw::__WASI_ESUCCESS,
+        "advising the kernel"
+    );
+
+    close_fd(file_fd);
+    cleanup_file(dir_fd, "file");
+}
+fn main() {
+    let mut args = env::args();
+    let prog = args.next().unwrap();
+    let arg = if let Some(arg) = args.next() {
+        arg
+    } else {
+        eprintln!("usage: {} <scratch directory>", prog);
+        process::exit(1);
+    };
+
+    // Open scratch directory
+    let dir_fd = match open_scratch_directory(&arg) {
+        Ok(dir_fd) => dir_fd,
+        Err(err) => {
+            eprintln!("{}", err);
+            process::exit(1)
+        }
+    };
+
+    // Run the tests.
+    unsafe { test_fd_advise(dir_fd) }
+}

crates/test-programs/wasi-tests/src/bin/fd_filestat_set.rs

@@ -0,0 +1,120 @@
+use libc;
+use more_asserts::assert_gt;
+use std::{env, process};
+use wasi::wasi_unstable;
+use wasi_tests::open_scratch_directory;
+use wasi_tests::utils::{cleanup_file, close_fd};
+use wasi_tests::wasi_wrappers::{wasi_fd_filestat_get, wasi_path_open};
+
+unsafe fn test_fd_filestat_set(dir_fd: wasi_unstable::Fd) {
+    // Create a file in the scratch directory.
+    let mut file_fd = wasi_unstable::Fd::max_value() - 1;
+    let status = wasi_path_open(
+        dir_fd,
+        0,
+        "file",
+        wasi_unstable::O_CREAT,
+        wasi_unstable::RIGHT_FD_READ | wasi_unstable::RIGHT_FD_WRITE,
+        0,
+        0,
+        &mut file_fd,
+    );
+    assert_eq!(
+        status,
+        wasi_unstable::raw::__WASI_ESUCCESS,
+        "opening a file"
+    );
+    assert_gt!(
+        file_fd,
+        libc::STDERR_FILENO as wasi_unstable::Fd,
+        "file descriptor range check",
+    );
+
+    // Check file size
+    let mut stat = wasi_unstable::FileStat {
+        st_dev: 0,
+        st_ino: 0,
+        st_filetype: 0,
+        st_nlink: 0,
+        st_size: 0,
+        st_atim: 0,
+        st_mtim: 0,
+        st_ctim: 0,
+    };
+    let status = wasi_fd_filestat_get(file_fd, &mut stat);
+    assert_eq!(
+        status,
+        wasi_unstable::raw::__WASI_ESUCCESS,
+        "reading file stats"
+    );
+    assert_eq!(stat.st_size, 0, "file size should be 0");
+
+    // Check fd_filestat_set_size
+    assert!(
+        wasi_unstable::fd_filestat_set_size(file_fd, 100).is_ok(),
+        "fd_filestat_set_size"
+    );
+
+    let status = wasi_fd_filestat_get(file_fd, &mut stat);
+    assert_eq!(
+        status,
+        wasi_unstable::raw::__WASI_ESUCCESS,
+        "reading file stats after fd_filestat_set_size"
+    );
+    assert_eq!(stat.st_size, 100, "file size should be 100");
+
+    // Check fd_filestat_set_times
+    let old_atim = stat.st_atim;
+    let new_mtim = stat.st_mtim - 100;
+    assert!(
+        wasi_unstable::fd_filestat_set_times(
+            file_fd,
+            new_mtim,
+            new_mtim,
+            wasi_unstable::FILESTAT_SET_MTIM,
+        )
+        .is_ok(),
+        "fd_filestat_set_times"
+    );
+
+    let status = wasi_fd_filestat_get(file_fd, &mut stat);
+    assert_eq!(
+        status,
+        wasi_unstable::raw::__WASI_ESUCCESS,
+        "reading file stats after fd_filestat_set_times"
+    );
+    assert_eq!(
+        stat.st_size, 100,
+        "file size should remain unchanged at 100"
+    );
+    assert_eq!(stat.st_mtim, new_mtim, "mtim should change");
+    assert_eq!(stat.st_atim, old_atim, "atim should not change");
+
+    // let status = wasi_fd_filestat_set_times(file_fd, new_mtim, new_mtim, wasi_unstable::FILESTAT_SET_MTIM | wasi_unstable::FILESTAT_SET_MTIM_NOW);
+    // assert_eq!(status, wasi_unstable::EINVAL, "ATIM & ATIM_NOW can't both be set");
+
+    close_fd(file_fd);
+    cleanup_file(dir_fd, "file");
+}
+fn main() {
+    let mut args = env::args();
+    let prog = args.next().unwrap();
+    let arg = if let Some(arg) = args.next() {
+        arg
+    } else {
+        eprintln!("usage: {} <scratch directory>", prog);
+        process::exit(1);
+    };
+
+    // Open scratch directory
+    let dir_fd = match open_scratch_directory(&arg) {
+        Ok(dir_fd) => dir_fd,
+        Err(err) => {
+            eprintln!("{}", err);
+            process::exit(1)
+        }
+    };
+
+    // Run the tests.
+    unsafe { test_fd_filestat_set(dir_fd) }
+}

crates/test-programs/wasi-tests/src/bin/fd_readdir.rs

@@ -0,0 +1,189 @@
+use libc;
+use more_asserts::assert_gt;
+use std::{cmp::min, env, mem, process, slice, str};
+use wasi::wasi_unstable;
+use wasi_tests::open_scratch_directory;
+use wasi_tests::wasi_wrappers::{wasi_fd_filestat_get, wasi_fd_readdir, wasi_path_open};
+
+const BUF_LEN: usize = 256;
+
+#[derive(Debug)]
+struct DirEntry {
+    dirent: wasi_unstable::Dirent,
+    name: String,
+}
+
+// Manually reading the output from fd_readdir is tedious and repetitive,
+// so encapsulate it into an iterator
+struct ReadDir<'a> {
+    buf: &'a [u8],
+}
+
+impl<'a> ReadDir<'a> {
+    fn from_slice(buf: &'a [u8]) -> Self {
+        Self { buf }
+    }
+}
+
+impl<'a> Iterator for ReadDir<'a> {
+    type Item = DirEntry;
+
+    fn next(&mut self) -> Option<DirEntry> {
+        unsafe {
+            if self.buf.is_empty() {
+                return None;
+            }
+
+            // Read the data
+            let dirent_ptr = self.buf.as_ptr() as *const wasi_unstable::Dirent;
+            let dirent = *dirent_ptr;
+            let name_ptr = dirent_ptr.offset(1) as *const u8;
+            // NOTE Linux syscall returns a NULL-terminated name, but WASI doesn't
+            let namelen = dirent.d_namlen as usize;
+            let slice = slice::from_raw_parts(name_ptr, namelen);
+            let name = str::from_utf8(slice).expect("invalid utf8").to_owned();
+
+            // Update the internal state
+            let delta = mem::size_of_val(&dirent) + namelen;
+            self.buf = &self.buf[delta..];
+
+            DirEntry { dirent, name }.into()
+        }
+    }
+}
+
+unsafe fn exec_fd_readdir(
+    fd: wasi_unstable::Fd,
+    cookie: wasi_unstable::DirCookie,
+) -> Vec<DirEntry> {
+    let mut buf: [u8; BUF_LEN] = [0; BUF_LEN];
+    let mut bufused = 0;
+    let status = wasi_fd_readdir(fd, &mut buf, BUF_LEN, cookie, &mut bufused);
+    assert_eq!(status, wasi_unstable::raw::__WASI_ESUCCESS, "fd_readdir");
+
+    let sl = slice::from_raw_parts(buf.as_ptr(), min(BUF_LEN, bufused));
+    let dirs: Vec<_> = ReadDir::from_slice(sl).collect();
+    dirs
+}
+
+unsafe fn test_fd_readdir(dir_fd: wasi_unstable::Fd) {
+    let mut stat: wasi_unstable::FileStat = mem::zeroed();
+    let status = wasi_fd_filestat_get(dir_fd, &mut stat);
+    assert_eq!(
+        status,
+        wasi_unstable::raw::__WASI_ESUCCESS,
+        "reading scratch directory stats"
+    );
+
+    // Check the behavior in an empty directory
+    let mut dirs = exec_fd_readdir(dir_fd, wasi_unstable::DIRCOOKIE_START);
+    dirs.sort_by_key(|d| d.name.clone());
+    assert_eq!(dirs.len(), 2, "expected two entries in an empty directory");
+    let mut dirs = dirs.into_iter();
+
+    // the first entry should be `.`
+    let dir = dirs.next().expect("first entry is None");
+    assert_eq!(dir.name, ".", "first name");
+    assert_eq!(
+        dir.dirent.d_type,
+        wasi_unstable::FILETYPE_DIRECTORY,
+        "first type"
+    );
+    assert_eq!(dir.dirent.d_ino, stat.st_ino);
+    assert_eq!(dir.dirent.d_namlen, 1);
+
+    // the second entry should be `..`
+    let dir = dirs.next().expect("second entry is None");
+    assert_eq!(dir.name, "..", "second name");
+    assert_eq!(
+        dir.dirent.d_type,
+        wasi_unstable::FILETYPE_DIRECTORY,
+        "second type"
+    );
+
+    assert!(
+        dirs.next().is_none(),
+        "the directory should be seen as empty"
+    );
+
+    // Add a file and check the behavior
+    let mut file_fd = wasi_unstable::Fd::max_value() - 1;
+    let status = wasi_path_open(
+        dir_fd,
+        0,
+        "file",
+        wasi_unstable::O_CREAT,
+        wasi_unstable::RIGHT_FD_READ | wasi_unstable::RIGHT_FD_WRITE,
+        0,
+        0,
+        &mut file_fd,
+    );
+    assert_eq!(
+        status,
+        wasi_unstable::raw::__WASI_ESUCCESS,
+        "opening a file"
+    );
+    assert_gt!(
+        file_fd,
+        libc::STDERR_FILENO as wasi_unstable::Fd,
+        "file descriptor range check",
+    );
+
+    let status = wasi_fd_filestat_get(file_fd, &mut stat);
+    assert_eq!(
+        status,
+        wasi_unstable::raw::__WASI_ESUCCESS,
+        "reading file stats"
+    );
+
+    // Execute another readdir
+    let mut dirs = exec_fd_readdir(dir_fd, wasi_unstable::DIRCOOKIE_START);
+    assert_eq!(dirs.len(), 3, "expected three entries");
+    // Save the data about the last entry. We need to do it before sorting.
+    let lastfile_cookie = dirs[1].dirent.d_next;
+    let lastfile_name = dirs[2].name.clone();
+    dirs.sort_by_key(|d| d.name.clone());
+    let mut dirs = dirs.into_iter();
+
+    let dir = dirs.next().expect("first entry is None");
+    assert_eq!(dir.name, ".", "first name");
+    let dir = dirs.next().expect("second entry is None");
+    assert_eq!(dir.name, "..", "second name");
+    let dir = dirs.next().expect("third entry is None");
+    // check the file info
+    assert_eq!(dir.name, "file", "file name doesn't match");
+    assert_eq!(
+        dir.dirent.d_type,
+        wasi_unstable::FILETYPE_REGULAR_FILE,
+        "type for the real file"
+    );
+    assert_eq!(dir.dirent.d_ino, stat.st_ino);
+
+    // check if cookie works as expected
+    let dirs = exec_fd_readdir(dir_fd, lastfile_cookie);
+    assert_eq!(dirs.len(), 1, "expected one entry");
+    assert_eq!(dirs[0].name, lastfile_name, "name of the only entry");
+}
+
+fn main() {
+    let mut args = env::args();
+    let prog = args.next().unwrap();
+    let arg = if let Some(arg) = args.next() {
+        arg
+    } else {
+        eprintln!("usage: {} <scratch directory>", prog);
+        process::exit(1);
+    };
+
+    // Open scratch directory
+    let dir_fd = match open_scratch_directory(&arg) {
+        Ok(dir_fd) => dir_fd,
+        Err(err) => {
+            eprintln!("{}", err);
+            process::exit(1)
+        }
+    };
+
+    // Run the tests.
+    unsafe { test_fd_readdir(dir_fd) }
+}

crates/test-programs/wasi-tests/src/bin/file_allocate.rs

@@ -0,0 +1,124 @@
+use more_asserts::assert_gt;
+use std::{env, process};
+use wasi::wasi_unstable;
+use wasi_tests::open_scratch_directory;
+use wasi_tests::utils::{cleanup_file, close_fd};
+use wasi_tests::wasi_wrappers::{wasi_fd_filestat_get, wasi_path_open};
+
+unsafe fn test_file_allocate(dir_fd: wasi_unstable::Fd) {
+    // Create a file in the scratch directory.
+    let mut file_fd = wasi_unstable::Fd::max_value() - 1;
+    let status = wasi_path_open(
+        dir_fd,
+        0,
+        "file",
+        wasi_unstable::O_CREAT,
+        wasi_unstable::RIGHT_FD_READ | wasi_unstable::RIGHT_FD_WRITE,
+        0,
+        0,
+        &mut file_fd,
+    );
+    assert_eq!(
+        status,
+        wasi_unstable::raw::__WASI_ESUCCESS,
+        "opening a file"
+    );
+    assert_gt!(
+        file_fd,
+        libc::STDERR_FILENO as wasi_unstable::Fd,
+        "file descriptor range check",
+    );
+
+    // Check file size
+    let mut stat = wasi_unstable::FileStat {
+        st_dev: 0,
+        st_ino: 0,
+        st_filetype: 0,
+        st_nlink: 0,
+        st_size: 0,
+        st_atim: 0,
+        st_mtim: 0,
+        st_ctim: 0,
+    };
+    let status = wasi_fd_filestat_get(file_fd, &mut stat);
+    assert_eq!(
+        status,
+        wasi_unstable::raw::__WASI_ESUCCESS,
+        "reading file stats"
+    );
+    assert_eq!(stat.st_size, 0, "file size should be 0");
+
+    // Allocate some size
+    assert!(
+        wasi_unstable::fd_allocate(file_fd, 0, 100).is_ok(),
+        "allocating size"
+    );
+
+    let status = wasi_fd_filestat_get(file_fd, &mut stat);
+    assert_eq!(
+        status,
+        wasi_unstable::raw::__WASI_ESUCCESS,
+        "reading file stats after initial allocation"
+    );
+    assert_eq!(stat.st_size, 100, "file size should be 100");
+
+    // Allocate should not modify if less than current size
+    assert!(
+        wasi_unstable::fd_allocate(file_fd, 10, 10).is_ok(),
+        "allocating size less than current size"
+    );
+
+    let status = wasi_fd_filestat_get(file_fd, &mut stat);
+    assert_eq!(
+        status,
+        wasi_unstable::raw::__WASI_ESUCCESS,
+        "reading file stats after additional allocation was not required"
+    );
+    assert_eq!(
+        stat.st_size, 100,
+        "file size should remain unchanged at 100"
+    );
+
+    // Allocate should modify if offset+len > current_len
+    assert!(
+        wasi_unstable::fd_allocate(file_fd, 90, 20).is_ok(),
+        "allocating size larger than current size"
+    );
+
+    let status = wasi_fd_filestat_get(file_fd, &mut stat);
+    assert_eq!(
+        status,
+        wasi_unstable::raw::__WASI_ESUCCESS,
+        "reading file stats after additional allocation was required"
+    );
+    assert_eq!(
+        stat.st_size, 110,
+        "file size should increase from 100 to 110"
+    );
+
+    close_fd(file_fd);
+    cleanup_file(dir_fd, "file");
+}
+
+fn main() {
+    let mut args = env::args();
+    let prog = args.next().unwrap();
+    let arg = if let Some(arg) = args.next() {
+        arg
+    } else {
+        eprintln!("usage: {} <scratch directory>", prog);
+        process::exit(1);
+    };
+
+    // Open scratch directory
+    let dir_fd = match open_scratch_directory(&arg) {
+        Ok(dir_fd) => dir_fd,
+        Err(err) => {
+            eprintln!("{}", err);
+            process::exit(1)
+        }
+    };
+
+    // Run the tests.
+    unsafe { test_file_allocate(dir_fd) }
+}

crates/test-programs/wasi-tests/src/bin/file_pread_pwrite.rs

@@ -0,0 +1,131 @@
+use libc;
+use more_asserts::assert_gt;
+use std::{env, process};
+use wasi::wasi_unstable;
+use wasi_tests::open_scratch_directory;
+use wasi_tests::utils::{cleanup_file, close_fd};
+use wasi_tests::wasi_wrappers::{wasi_fd_pread, wasi_fd_pwrite, wasi_path_open};
+
+unsafe fn test_file_pread_pwrite(dir_fd: wasi_unstable::Fd) {
+    // Create a file in the scratch directory.
+    let mut file_fd = wasi_unstable::Fd::max_value() - 1;
+    let mut status = wasi_path_open(
+        dir_fd,
+        0,
+        "file",
+        wasi_unstable::O_CREAT,
+        wasi_unstable::RIGHT_FD_READ | wasi_unstable::RIGHT_FD_WRITE,
+        0,
+        0,
+        &mut file_fd,
+    );
+    assert_eq!(
+        status,
+        wasi_unstable::raw::__WASI_ESUCCESS,
+        "opening a file"
+    );
+    assert_gt!(
+        file_fd,
+        libc::STDERR_FILENO as wasi_unstable::Fd,
+        "file descriptor range check",
+    );
+
+    let contents = &[0u8, 1, 2, 3];
+    let ciovec = wasi_unstable::CIoVec {
+        buf: contents.as_ptr() as *const libc::c_void,
+        buf_len: contents.len(),
+    };
+    let mut nwritten = 0;
+    status = wasi_fd_pwrite(file_fd, &mut [ciovec], 0, &mut nwritten);
+    assert_eq!(
+        status,
+        wasi_unstable::raw::__WASI_ESUCCESS,
+        "writing bytes at offset 0"
+    );
+    assert_eq!(nwritten, 4, "nwritten bytes check");
+
+    let contents = &mut [0u8; 4];
+    let iovec = wasi_unstable::IoVec {
+        buf: contents.as_mut_ptr() as *mut libc::c_void,
+        buf_len: contents.len(),
+    };
+    let mut nread = 0;
+    status = wasi_fd_pread(file_fd, &[iovec], 0, &mut nread);
+    assert_eq!(
+        status,
+        wasi_unstable::raw::__WASI_ESUCCESS,
+        "reading bytes at offset 0"
+    );
+    assert_eq!(nread, 4, "nread bytes check");
+    assert_eq!(contents, &[0u8, 1, 2, 3], "written bytes equal read bytes");
+
+    let contents = &mut [0u8; 4];
+    let iovec = wasi_unstable::IoVec {
+        buf: contents.as_mut_ptr() as *mut libc::c_void,
+        buf_len: contents.len(),
+    };
+    let mut nread = 0;
+    status = wasi_fd_pread(file_fd, &[iovec], 2, &mut nread);
+    assert_eq!(
+        status,
+        wasi_unstable::raw::__WASI_ESUCCESS,
+        "reading bytes at offset 2"
+    );
+    assert_eq!(nread, 2, "nread bytes check");
+    assert_eq!(contents, &[2u8, 3, 0, 0], "file cursor was overwritten");
+
+    let contents = &[1u8, 0];
+    let ciovec = wasi_unstable::CIoVec {
+        buf: contents.as_ptr() as *const libc::c_void,
+        buf_len: contents.len(),
+    };
+    let mut nwritten = 0;
+    status = wasi_fd_pwrite(file_fd, &mut [ciovec], 2, &mut nwritten);
+    assert_eq!(
+        status,
+        wasi_unstable::raw::__WASI_ESUCCESS,
+        "writing bytes at offset 2"
+    );
+    assert_eq!(nwritten, 2, "nwritten bytes check");
+
+    let contents = &mut [0u8; 4];
+    let iovec = wasi_unstable::IoVec {
+        buf: contents.as_mut_ptr() as *mut libc::c_void,
+        buf_len: contents.len(),
+    };
+    let mut nread = 0;
+    status = wasi_fd_pread(file_fd, &[iovec], 0, &mut nread);
+    assert_eq!(
+        status,
+        wasi_unstable::raw::__WASI_ESUCCESS,
+        "reading bytes at offset 0"
+    );
+    assert_eq!(nread, 4, "nread bytes check");
+    assert_eq!(contents, &[0u8, 1, 1, 0], "file cursor was overwritten");
+
+    close_fd(file_fd);
+    cleanup_file(dir_fd, "file");
+}
+
+fn main() {
+    let mut args = env::args();
+    let prog = args.next().unwrap();
+    let arg = if let Some(arg) = args.next() {
+        arg
+    } else {
+        eprintln!("usage: {} <scratch directory>", prog);
+        process::exit(1);
+    };
+
+    // Open scratch directory
+    let dir_fd = match open_scratch_directory(&arg) {
+        Ok(dir_fd) => dir_fd,
+        Err(err) => {
+            eprintln!("{}", err);
+            process::exit(1)
+        }
+    };
+
+    // Run the tests.
+    unsafe { test_file_pread_pwrite(dir_fd) }
+}

crates/test-programs/wasi-tests/src/bin/file_seek_tell.rs

@@ -0,0 +1,133 @@
+use libc;
+use more_asserts::assert_gt;
+use std::{env, process};
+use wasi::wasi_unstable;
+use wasi_tests::open_scratch_directory;
+use wasi_tests::utils::{cleanup_file, close_fd};
+use wasi_tests::wasi_wrappers::{wasi_fd_seek, wasi_fd_tell, wasi_fd_write, wasi_path_open};
+
+unsafe fn test_file_seek_tell(dir_fd: wasi_unstable::Fd) {
+    // Create a file in the scratch directory.
+    let mut file_fd = wasi_unstable::Fd::max_value() - 1;
+    let mut status = wasi_path_open(
+        dir_fd,
+        0,
+        "file",
+        wasi_unstable::O_CREAT,
+        wasi_unstable::RIGHT_FD_READ | wasi_unstable::RIGHT_FD_WRITE,
+        0,
+        0,
+        &mut file_fd,
+    );
+    assert_eq!(
+        status,
+        wasi_unstable::raw::__WASI_ESUCCESS,
+        "opening a file"
+    );
+    assert_gt!(
+        file_fd,
+        libc::STDERR_FILENO as wasi_unstable::Fd,
+        "file descriptor range check",
+    );
+
+    // Check current offset
+    let mut offset: wasi_unstable::FileSize = 0;
+    status = wasi_fd_tell(file_fd, &mut offset);
+    assert_eq!(
+        status,
+        wasi_unstable::raw::__WASI_ESUCCESS,
+        "getting initial file offset"
+    );
+    assert_eq!(offset, 0, "current offset should be 0");
+
+    // Write to file
+    let buf = &[0u8; 100];
+    let iov = wasi_unstable::CIoVec {
+        buf: buf.as_ptr() as *const _,
+        buf_len: buf.len(),
+    };
+    let iovs = &[iov];
+    let mut nwritten = 0;
+    status = wasi_fd_write(file_fd, iovs, &mut nwritten);
+    assert_eq!(
+        status,
+        wasi_unstable::raw::__WASI_ESUCCESS,
+        "writing to a file"
+    );
+    assert_eq!(nwritten, 100, "should write 100 bytes to file");
+
+    // Check current offset
+    status = wasi_fd_tell(file_fd, &mut offset);
+    assert_eq!(
+        status,
+        wasi_unstable::raw::__WASI_ESUCCESS,
+        "getting file offset after writing"
+    );
+    assert_eq!(offset, 100, "offset after writing should be 100");
+
+    // Seek to middle of the file
+    let mut newoffset = 1;
+    status = wasi_fd_seek(file_fd, -50, wasi_unstable::WHENCE_CUR, &mut newoffset);
+    assert_eq!(
+        status,
+        wasi_unstable::raw::__WASI_ESUCCESS,
+        "seeking to the middle of a file"
+    );
+    assert_eq!(
+        newoffset, 50,
+        "offset after seeking to the middle should be at 50"
+    );
+
+    // Seek to the beginning of the file
+    status = wasi_fd_seek(file_fd, 0, wasi_unstable::WHENCE_SET, &mut newoffset);
+    assert_eq!(
+        status,
+        wasi_unstable::raw::__WASI_ESUCCESS,
+        "seeking to the beginning of the file"
+    );
+    assert_eq!(
+        newoffset, 0,
+        "offset after seeking to the beginning of the file should be at 0"
+    );
+
+    // Seek beyond the file should be possible
+    status = wasi_fd_seek(file_fd, 1000, wasi_unstable::WHENCE_CUR, &mut newoffset);
+    assert_eq!(
+        status,
+        wasi_unstable::raw::__WASI_ESUCCESS,
+        "seeking beyond the end of the file"
+    );
+
+    // Seek before byte 0 is an error though
+    status = wasi_fd_seek(file_fd, -2000, wasi_unstable::WHENCE_CUR, &mut newoffset);
+    assert_eq!(
+        status,
+        wasi_unstable::raw::__WASI_EINVAL,
+        "seeking before byte 0 is an error"
+    );
+
+    close_fd(file_fd);
+    cleanup_file(dir_fd, "file");
+}
+fn main() {
+    let mut args = env::args();
+    let prog = args.next().unwrap();
+    let arg = if let Some(arg) = args.next() {
+        arg
+    } else {
+        eprintln!("usage: {} <scratch directory>", prog);
+        process::exit(1);
+    };
+
+    // Open scratch directory
+    let dir_fd = match open_scratch_directory(&arg) {
+        Ok(dir_fd) => dir_fd,
+        Err(err) => {
+            eprintln!("{}", err);
+            process::exit(1)
+        }
+    };
+
+    // Run the tests.
+    unsafe { test_file_seek_tell(dir_fd) }
+}

crates/test-programs/wasi-tests/src/bin/file_unbuffered_write.rs

@@ -0,0 +1,115 @@
+use more_asserts::assert_gt;
+use std::{env, process};
+use wasi::wasi_unstable;
+use wasi_tests::open_scratch_directory;
+use wasi_tests::utils::{cleanup_file, close_fd, create_file};
+use wasi_tests::wasi_wrappers::{wasi_fd_read, wasi_fd_write, wasi_path_open};
+
+unsafe fn test_file_unbuffered_write(dir_fd: wasi_unstable::Fd) {
+    // Create file
+    create_file(dir_fd, "file");
+
+    // Open file for reading
+    let mut fd_read = wasi_unstable::Fd::max_value() - 1;
+    let mut status = wasi_path_open(
+        dir_fd,
+        0,
+        "file",
+        0,
+        wasi_unstable::RIGHT_FD_READ,
+        0,
+        0,
+        &mut fd_read,
+    );
+    assert_eq!(
+        status,
+        wasi_unstable::raw::__WASI_ESUCCESS,
+        "opening a file"
+    );
+    assert_gt!(
+        fd_read,
+        libc::STDERR_FILENO as wasi_unstable::Fd,
+        "file descriptor range check",
+    );
+
+    // Open the same file but for writing
+    let mut fd_write = wasi_unstable::Fd::max_value() - 1;
+    status = wasi_path_open(
+        dir_fd,
+        0,
+        "file",
+        0,
+        wasi_unstable::RIGHT_FD_WRITE,
+        0,
+        0,
+        &mut fd_write,
+    );
+    assert_eq!(
+        status,
+        wasi_unstable::raw::__WASI_ESUCCESS,
+        "opening a file"
+    );
+    assert_gt!(
+        fd_write,
+        libc::STDERR_FILENO as wasi_unstable::Fd,
+        "file descriptor range check",
+    );
+
+    // Write to file
+    let contents = &[1u8];
+    let ciovec = wasi_unstable::CIoVec {
+        buf: contents.as_ptr() as *const libc::c_void,
+        buf_len: contents.len(),
+    };
+    let mut nwritten = 0;
+    status = wasi_fd_write(fd_write, &[ciovec], &mut nwritten);
+    assert_eq!(
+        status,
+        wasi_unstable::raw::__WASI_ESUCCESS,
+        "writing byte to file"
+    );
+    assert_eq!(nwritten, 1, "nwritten bytes check");
+
+    // Read from file
+    let contents = &mut [0u8; 1];
+    let iovec = wasi_unstable::IoVec {
+        buf: contents.as_mut_ptr() as *mut libc::c_void,
+        buf_len: contents.len(),
+    };
+    let mut nread = 0;
+    status = wasi_fd_read(fd_read, &[iovec], &mut nread);
+    assert_eq!(
+        status,
+        wasi_unstable::raw::__WASI_ESUCCESS,
+        "reading bytes from file"
+    );
+    assert_eq!(nread, 1, "nread bytes check");
+    assert_eq!(contents, &[1u8], "written bytes equal read bytes");
+
+    // Clean up
+    close_fd(fd_write);
+    close_fd(fd_read);
+    cleanup_file(dir_fd, "file");
+}
+fn main() {
+    let mut args = env::args();
+    let prog = args.next().unwrap();
+    let arg = if let Some(arg) = args.next() {
+        arg
+    } else {
+        eprintln!("usage: {} <scratch directory>", prog);
+        process::exit(1);
+    };
+
+    // Open scratch directory
+    let dir_fd = match open_scratch_directory(&arg) {
+        Ok(dir_fd) => dir_fd,
+        Err(err) => {
+            eprintln!("{}", err);
+            process::exit(1)
+        }
+    };
+
+    // Run the tests.
+    unsafe { test_file_unbuffered_write(dir_fd) }
+}

crates/test-programs/wasi-tests/src/bin/interesting_paths.rs

@@ -0,0 +1,173 @@
+use libc;
+use more_asserts::assert_gt;
+use std::{env, process};
+use wasi::wasi_unstable;
+use wasi_tests::open_scratch_directory;
+use wasi_tests::utils::{close_fd, create_dir, create_file};
+use wasi_tests::wasi_wrappers::{
+    wasi_path_open, wasi_path_remove_directory, wasi_path_unlink_file,
+};
+
+unsafe fn test_interesting_paths(dir_fd: wasi_unstable::Fd, arg: &str) {
+    // Create a directory in the scratch directory.
+    create_dir(dir_fd, "dir");
+
+    // Create a directory in the directory we just created.
+    create_dir(dir_fd, "dir/nested");
+
+    // Create a file in the nested directory.
+    create_file(dir_fd, "dir/nested/file");
+
+    // Now open it with an absolute path.
+    let mut file_fd: wasi_unstable::Fd = wasi_unstable::Fd::max_value() - 1;
+    let mut status = wasi_path_open(dir_fd, 0, "/dir/nested/file", 0, 0, 0, 0, &mut file_fd);
+    assert_eq!(
+        status,
+        wasi_unstable::raw::__WASI_ENOTCAPABLE,
+        "opening a file with an absolute path"
+    );
+    assert_eq!(
+        file_fd,
+        wasi_unstable::Fd::max_value(),
+        "failed open should set the file descriptor to -1",
+    );
+
+    // Now open it with a path containing "..".
+    status = wasi_path_open(
+        dir_fd,
+        0,
+        "dir/.//nested/../../dir/nested/../nested///./file",
+        0,
+        0,
+        0,
+        0,
+        &mut file_fd,
+    );
+    assert_eq!(
+        status,
+        wasi_unstable::raw::__WASI_ESUCCESS,
+        "opening a file with \"..\" in the path"
+    );
+    assert_gt!(
+        file_fd,
+        libc::STDERR_FILENO as wasi_unstable::Fd,
+        "file descriptor range check",
+    );
+    close_fd(file_fd);
+
+    // Now open it with a trailing NUL.
+    status = wasi_path_open(dir_fd, 0, "dir/nested/file\0", 0, 0, 0, 0, &mut file_fd);
+    assert_eq!(
+        status,
+        wasi_unstable::raw::__WASI_EILSEQ,
+        "opening a file with a trailing NUL"
+    );
+    assert_eq!(
+        file_fd,
+        wasi_unstable::Fd::max_value(),
+        "failed open should set the file descriptor to -1",
+    );
+
+    // Now open it with a trailing slash.
+    status = wasi_path_open(dir_fd, 0, "dir/nested/file/", 0, 0, 0, 0, &mut file_fd);
+    assert_eq!(
+        status,
+        wasi_unstable::raw::__WASI_ENOTDIR,
+        "opening a file with a trailing slash"
+    );
+    assert_eq!(
+        file_fd,
+        wasi_unstable::Fd::max_value(),
+        "failed open should set the file descriptor to -1",
+    );
+
+    // Now open it with trailing slashes.
+    status = wasi_path_open(dir_fd, 0, "dir/nested/file///", 0, 0, 0, 0, &mut file_fd);
+    assert_eq!(
+        status,
+        wasi_unstable::raw::__WASI_ENOTDIR,
+        "opening a file with trailing slashes"
+    );
+    assert_eq!(
+        file_fd,
+        wasi_unstable::Fd::max_value(),
+        "failed open should set the file descriptor to -1",
+    );
+
+    // Now open the directory with a trailing slash.
+    status = wasi_path_open(dir_fd, 0, "dir/nested/", 0, 0, 0, 0, &mut file_fd);
+    assert_eq!(
+        status,
+        wasi_unstable::raw::__WASI_ESUCCESS,
+        "opening a directory with a trailing slash"
+    );
+    assert_gt!(
+        file_fd,
+        libc::STDERR_FILENO as wasi_unstable::Fd,
+        "file descriptor range check",
+    );
+    close_fd(file_fd);
+
+    // Now open the directory with trailing slashes.
+    status = wasi_path_open(dir_fd, 0, "dir/nested///", 0, 0, 0, 0, &mut file_fd);
+    assert_eq!(
+        status,
+        wasi_unstable::raw::__WASI_ESUCCESS,
+        "opening a directory with trailing slashes"
+    );
+    assert_gt!(
+        file_fd,
+        libc::STDERR_FILENO as wasi_unstable::Fd,
+        "file descriptor range check",
+    );
+    close_fd(file_fd);
+
+    // Now open it with a path containing too many ".."s.
+    let bad_path = format!("dir/nested/../../../{}/dir/nested/file", arg);
+    status = wasi_path_open(dir_fd, 0, &bad_path, 0, 0, 0, 0, &mut file_fd);
+    assert_eq!(
+        status,
+        wasi_unstable::raw::__WASI_ENOTCAPABLE,
+        "opening a file with too many \"..\"s in the path"
+    );
+    assert_eq!(
+        file_fd,
+        wasi_unstable::Fd::max_value(),
+        "failed open should set the file descriptor to -1",
+    );
+    assert!(
+        wasi_path_unlink_file(dir_fd, "dir/nested/file").is_ok(),
+        "unlink_file on a symlink should succeed"
+    );
+    assert!(
+        wasi_path_remove_directory(dir_fd, "dir/nested").is_ok(),
+        "remove_directory on a directory should succeed"
+    );
+    assert!(
+        wasi_path_remove_directory(dir_fd, "dir").is_ok(),
+        "remove_directory on a directory should succeed"
+    );
+}
+
+fn main() {
+    let mut args = env::args();
+    let prog = args.next().unwrap();
+    let arg = if let Some(arg) = args.next() {
+        arg
+    } else {
+        eprintln!("usage: {} <scratch directory>", prog);
+        process::exit(1);
+    };
+
+    // Open scratch directory
+    let dir_fd = match open_scratch_directory(&arg) {
+        Ok(dir_fd) => dir_fd,
+        Err(err) => {
+            eprintln!("{}", err);
+            process::exit(1)
+        }
+    };
+
+    // Run the tests.
+    unsafe { test_interesting_paths(dir_fd, &arg) }
+}

crates/test-programs/wasi-tests/src/bin/isatty.rs

@@ -0,0 +1,62 @@
+use more_asserts::assert_gt;
+use std::{env, process};
+use wasi::wasi_unstable;
+use wasi_tests::open_scratch_directory;
+use wasi_tests::utils::{cleanup_file, close_fd};
+use wasi_tests::wasi_wrappers::wasi_path_open;
+
+unsafe fn test_isatty(dir_fd: wasi_unstable::Fd) {
+    // Create a file in the scratch directory and test if it's a tty.
+    let mut file_fd: wasi_unstable::Fd = wasi_unstable::Fd::max_value() - 1;
+    let status = wasi_path_open(
+        dir_fd,
+        0,
+        "file",
+        wasi_unstable::O_CREAT,
+        0,
+        0,
+        0,
+        &mut file_fd,
+    );
+    assert_eq!(
+        status,
+        wasi_unstable::raw::__WASI_ESUCCESS,
+        "opening a file"
+    );
+    assert_gt!(
+        file_fd,
+        libc::STDERR_FILENO as wasi_unstable::Fd,
+        "file descriptor range check",
+    );
+    assert_eq!(
+        libc::isatty(file_fd as std::os::raw::c_int),
+        0,
+        "file is a tty"
+    );
+    close_fd(file_fd);
+
+    cleanup_file(dir_fd, "file");
+}
+
+fn main() {
+    let mut args = env::args();
+    let prog = args.next().unwrap();
+    let arg = if let Some(arg) = args.next() {
+        arg
+    } else {
+        eprintln!("usage: {} <scratch directory>", prog);
+        process::exit(1);
+    };
+
+    // Open scratch directory
+    let dir_fd = match open_scratch_directory(&arg) {
+        Ok(dir_fd) => dir_fd,
+        Err(err) => {
+            eprintln!("{}", err);
+            process::exit(1)
+        }
+    };
+
+    // Run the tests.
+    unsafe { test_isatty(dir_fd) }
+}

crates/test-programs/wasi-tests/src/bin/nofollow_errors.rs

@@ -0,0 +1,175 @@
+use libc;
+use more_asserts::assert_gt;
+use std::{env, process};
+use wasi::wasi_unstable;
+use wasi_tests::open_scratch_directory;
+use wasi_tests::utils::{cleanup_file, close_fd, create_dir, create_file};
+use wasi_tests::wasi_wrappers::{wasi_path_open, wasi_path_remove_directory, wasi_path_symlink};
+
+unsafe fn test_nofollow_errors(dir_fd: wasi_unstable::Fd) {
+    // Create a directory for the symlink to point to.
+    create_dir(dir_fd, "target");
+
+    // Create a symlink.
+    assert!(
+        wasi_path_symlink("target", dir_fd, "symlink").is_ok(),
+        "creating a symlink"
+    );
+
+    // Try to open it as a directory with O_NOFOLLOW again.
+    let mut file_fd: wasi_unstable::Fd = wasi_unstable::Fd::max_value() - 1;
+    let mut status = wasi_path_open(
+        dir_fd,
+        0,
+        "symlink",
+        wasi_unstable::O_DIRECTORY,
+        0,
+        0,
+        0,
+        &mut file_fd,
+    );
+    assert_eq!(
+        status,
+        wasi_unstable::raw::__WASI_ELOOP,
+        "opening a directory symlink as a directory",
+    );
+    assert_eq!(
+        file_fd,
+        wasi_unstable::Fd::max_value(),
+        "failed open should set the file descriptor to -1",
+    );
+
+    // Try to open it with just O_NOFOLLOW.
+    status = wasi_path_open(dir_fd, 0, "symlink", 0, 0, 0, 0, &mut file_fd);
+    assert_eq!(
+        status,
+        wasi_unstable::raw::__WASI_ELOOP,
+        "opening a symlink with O_NOFOLLOW should return ELOOP",
+    );
+    assert_eq!(
+        file_fd,
+        wasi_unstable::Fd::max_value(),
+        "failed open should set the file descriptor to -1",
+    );
+
+    // Try to open it as a directory without O_NOFOLLOW.
+    status = wasi_path_open(
+        dir_fd,
+        wasi_unstable::LOOKUP_SYMLINK_FOLLOW,
+        "symlink",
+        wasi_unstable::O_DIRECTORY,
+        0,
+        0,
+        0,
+        &mut file_fd,
+    );
+    assert_eq!(
+        status,
+        wasi_unstable::raw::__WASI_ESUCCESS,
+        "opening a symlink as a directory"
+    );
+    assert_gt!(
+        file_fd,
+        libc::STDERR_FILENO as wasi_unstable::Fd,
+        "file descriptor range check",
+    );
+    close_fd(file_fd);
+
+    // Replace the target directory with a file.
+    cleanup_file(dir_fd, "symlink");
+
+    assert!(
+        wasi_path_remove_directory(dir_fd, "target").is_ok(),
+        "remove_directory on a directory should succeed"
+    );
+    create_file(dir_fd, "target");
+
+    assert!(
+        wasi_path_symlink("target", dir_fd, "symlink").is_ok(),
+        "creating a symlink"
+    );
+
+    // Try to open it as a directory with O_NOFOLLOW again.
+    status = wasi_path_open(
+        dir_fd,
+        0,
+        "symlink",
+        wasi_unstable::O_DIRECTORY,
+        0,
+        0,
+        0,
+        &mut file_fd,
+    );
+    assert_eq!(
+        status,
+        wasi_unstable::raw::__WASI_ELOOP,
+        "opening a directory symlink as a directory",
+    );
+    assert_eq!(
+        file_fd,
+        wasi_unstable::Fd::max_value(),
+        "failed open should set the file descriptor to -1",
+    );
+
+    // Try to open it with just O_NOFOLLOW.
+    status = wasi_path_open(dir_fd, 0, "symlink", 0, 0, 0, 0, &mut file_fd);
+    assert_eq!(
+        status,
+        wasi_unstable::raw::__WASI_ELOOP,
+        "opening a symlink with O_NOFOLLOW should return ELOOP",
+    );
+    assert_eq!(
+        file_fd,
+        wasi_unstable::Fd::max_value(),
+        "failed open should set the file descriptor to -1",
+    );
+
+    // Try to open it as a directory without O_NOFOLLOW.
+    status = wasi_path_open(
+        dir_fd,
+        wasi_unstable::LOOKUP_SYMLINK_FOLLOW,
+        "symlink",
+        wasi_unstable::O_DIRECTORY,
+        0,
+        0,
+        0,
+        &mut file_fd,
+    );
+    assert_eq!(
+        status,
+        wasi_unstable::raw::__WASI_ENOTDIR,
+        "opening a symlink to a file as a directory",
+    );
+    assert_eq!(
+        file_fd,
+        wasi_unstable::Fd::max_value(),
+        "failed open should set the file descriptor to -1",
+    );
+
+    // Clean up.
+    cleanup_file(dir_fd, "target");
+    cleanup_file(dir_fd, "symlink");
+}
+
+fn main() {
+    let mut args = env::args();
+    let prog = args.next().unwrap();
+    let arg = if let Some(arg) = args.next() {
+        arg
+    } else {
+        eprintln!("usage: {} <scratch directory>", prog);
+        process::exit(1);
+    };
+
+    // Open scratch directory
+    let dir_fd = match open_scratch_directory(&arg) {
+        Ok(dir_fd) => dir_fd,
+        Err(err) => {
+            eprintln!("{}", err);
+            process::exit(1)
+        }
+    };
+
+    // Run the tests.
+    unsafe { test_nofollow_errors(dir_fd) }
+}

crates/test-programs/wasi-tests/src/bin/path_filestat.rs

@@ -0,0 +1,183 @@
+use more_asserts::assert_gt;
+use std::{env, process};
+use wasi::wasi_unstable;
+use wasi_tests::open_scratch_directory;
+use wasi_tests::utils::{cleanup_file, close_fd};
+use wasi_tests::wasi_wrappers::{
+    wasi_fd_fdstat_get, wasi_path_filestat_get, wasi_path_filestat_set_times, wasi_path_open,
+};
+
+unsafe fn test_path_filestat(dir_fd: wasi_unstable::Fd) {
+    let mut fdstat: wasi_unstable::FdStat = std::mem::zeroed();
+    let status = wasi_fd_fdstat_get(dir_fd, &mut fdstat);
+    assert_eq!(status, wasi_unstable::raw::__WASI_ESUCCESS, "fd_fdstat_get");
+
+    assert_ne!(
+        fdstat.fs_rights_base & wasi_unstable::RIGHT_PATH_FILESTAT_GET,
+        0,
+        "the scratch directory should have RIGHT_PATH_FILESTAT_GET as base right",
+    );
+    assert_ne!(
+        fdstat.fs_rights_inheriting & wasi_unstable::RIGHT_PATH_FILESTAT_GET,
+        0,
+        "the scratch directory should have RIGHT_PATH_FILESTAT_GET as base right",
+    );
+
+    // Create a file in the scratch directory.
+    let mut file_fd = wasi_unstable::Fd::max_value() - 1;
+    let filename = "file";
+    let status = wasi_path_open(
+        dir_fd,
+        0,
+        filename,
+        wasi_unstable::O_CREAT,
+        wasi_unstable::RIGHT_FD_READ
+            | wasi_unstable::RIGHT_FD_WRITE
+            | wasi_unstable::RIGHT_PATH_FILESTAT_GET,
+        0,
+        0,
+        &mut file_fd,
+    );
+    assert_eq!(
+        status,
+        wasi_unstable::raw::__WASI_ESUCCESS,
+        "opening a file"
+    );
+    assert_gt!(
+        file_fd,
+        libc::STDERR_FILENO as wasi_unstable::Fd,
+        "file descriptor range check",
+    );
+
+    let status = wasi_fd_fdstat_get(file_fd, &mut fdstat);
+    assert_eq!(status, wasi_unstable::raw::__WASI_ESUCCESS, "fd_fdstat_get");
+
+    assert_eq!(
+        fdstat.fs_rights_base & wasi_unstable::RIGHT_PATH_FILESTAT_GET,
+        0,
+        "files shouldn't have rights for path_* syscalls even if manually given",
+    );
+    assert_eq!(
+        fdstat.fs_rights_inheriting & wasi_unstable::RIGHT_PATH_FILESTAT_GET,
+        0,
+        "files shouldn't have rights for path_* syscalls even if manually given",
+    );
+
+    // Check file size
+    let mut stat = wasi_unstable::FileStat {
+        st_dev: 0,
+        st_ino: 0,
+        st_filetype: 0,
+        st_nlink: 0,
+        st_size: 0,
+        st_atim: 0,
+        st_mtim: 0,
+        st_ctim: 0,
+    };
+    let status = wasi_path_filestat_get(dir_fd, 0, filename, filename.len(), &mut stat);
+    assert_eq!(
+        status,
+        wasi_unstable::raw::__WASI_ESUCCESS,
+        "reading file stats"
+    );
+    assert_eq!(stat.st_size, 0, "file size should be 0");
+
+    // Check path_filestat_set_times
+    let old_atim = stat.st_atim;
+    let new_mtim = stat.st_mtim - 100;
+    assert!(
+        wasi_path_filestat_set_times(
+            dir_fd,
+            0,
+            filename,
+            // on purpose: the syscall should not touch atim, because
+            // neither of the ATIM flags is set
+            new_mtim,
+            new_mtim,
+            wasi_unstable::FILESTAT_SET_MTIM,
+        )
+        .is_ok(),
+        "path_filestat_set_times should succeed"
+    );
+
+    let status = wasi_path_filestat_get(dir_fd, 0, filename, filename.len(), &mut stat);
+    assert_eq!(
+        status,
+        wasi_unstable::raw::__WASI_ESUCCESS,
+        "reading file stats after path_filestat_set_times"
+    );
+    assert_eq!(stat.st_mtim, new_mtim, "mtim should change");
+    assert_eq!(stat.st_atim, old_atim, "atim should not change");
+
+    assert_eq!(
+        wasi_path_filestat_set_times(
+            dir_fd,
+            0,
+            filename,
+            new_mtim,
+            new_mtim,
+            wasi_unstable::FILESTAT_SET_MTIM | wasi_unstable::FILESTAT_SET_MTIM_NOW,
+        ),
+        Err(wasi_unstable::EINVAL),
+        "MTIM & MTIM_NOW can't both be set"
+    );
+
+    // check if the times were untouched
+    let status = wasi_path_filestat_get(dir_fd, 0, filename, filename.len(), &mut stat);
+    assert_eq!(
+        status,
+        wasi_unstable::raw::__WASI_ESUCCESS,
+        "reading file stats after EINVAL fd_filestat_set_times"
+    );
+    assert_eq!(stat.st_mtim, new_mtim, "mtim should not change");
+    assert_eq!(stat.st_atim, old_atim, "atim should not change");
+
+    let new_atim = old_atim - 100;
+    assert_eq!(
+        wasi_path_filestat_set_times(
+            dir_fd,
+            0,
+            filename,
+            new_atim,
+            new_atim,
+            wasi_unstable::FILESTAT_SET_ATIM | wasi_unstable::FILESTAT_SET_ATIM_NOW,
+        ),
+        Err(wasi_unstable::EINVAL),
+        "ATIM & ATIM_NOW can't both be set"
+    );
+
+    // check if the times were untouched
+    let status = wasi_path_filestat_get(dir_fd, 0, filename, filename.len(), &mut stat);
+    assert_eq!(
+        status,
+        wasi_unstable::raw::__WASI_ESUCCESS,
+        "reading file stats after EINVAL path_filestat_set_times"
+    );
+    assert_eq!(stat.st_mtim, new_mtim, "mtim should not change");
+    assert_eq!(stat.st_atim, old_atim, "atim should not change");
+
+    close_fd(file_fd);
+    cleanup_file(dir_fd, "file");
+}
+fn main() {
+    let mut args = env::args();
+    let prog = args.next().unwrap();
+    let arg = if let Some(arg) = args.next() {
+        arg
+    } else {
+        eprintln!("usage: {} <scratch directory>", prog);
+        process::exit(1);
+    };
+
+    // Open scratch directory
+    let dir_fd = match open_scratch_directory(&arg) {
+        Ok(dir_fd) => dir_fd,
+        Err(err) => {
+            eprintln!("{}", err);
+            process::exit(1)
+        }
+    };
+
+    // Run the tests.
+    unsafe { test_path_filestat(dir_fd) }
+}

crates/test-programs/wasi-tests/src/bin/path_link.rs

@@ -0,0 +1,271 @@
+use more_asserts::assert_gt;
+use std::{env, process};
+use wasi::wasi_unstable;
+use wasi_tests::open_scratch_directory;
+use wasi_tests::utils::{cleanup_dir, cleanup_file, create_dir, create_file};
+use wasi_tests::wasi_wrappers::{
+    wasi_fd_fdstat_get, wasi_fd_filestat_get, wasi_path_link, wasi_path_open, wasi_path_symlink,
+};
+
+unsafe fn create_or_open(
+    dir_fd: wasi_unstable::Fd,
+    name: &str,
+    flags: wasi_unstable::OFlags,
+) -> wasi_unstable::Fd {
+    let mut file_fd = wasi_unstable::Fd::max_value() - 1;
+    let mut status = wasi_path_open(dir_fd, 0, name, flags, 0, 0, 0, &mut file_fd);
+    assert_eq!(
+        status,
+        wasi_unstable::raw::__WASI_ESUCCESS,
+        "opening '{}'",
+        name
+    );
+    assert_gt!(
+        file_fd,
+        libc::STDERR_FILENO as wasi_unstable::Fd,
+        "file descriptor range check",
+    );
+    file_fd
+}
+
+unsafe fn open_link(dir_fd: wasi_unstable::Fd, name: &str) -> wasi_unstable::Fd {
+    let mut file_fd = wasi_unstable::Fd::max_value() - 1;
+    let mut status = wasi_path_open(dir_fd, 0, name, 0, 0, 0, 0, &mut file_fd);
+    assert_eq!(
+        status,
+        wasi_unstable::raw::__WASI_ESUCCESS,
+        "opening a link '{}'",
+        name
+    );
+    assert_gt!(
+        file_fd,
+        libc::STDERR_FILENO as wasi_unstable::Fd,
+        "file descriptor range check",
+    );
+    file_fd
+}
+
+unsafe fn check_rights(orig_fd: wasi_unstable::Fd, link_fd: wasi_unstable::Fd) {
+    use std::mem::MaybeUninit;
+
+    // Compare FileStats
+    let mut orig_filestat: wasi_unstable::FileStat = MaybeUninit::zeroed().assume_init();
+    let mut link_filestat: wasi_unstable::FileStat = MaybeUninit::zeroed().assume_init();
+    let mut status = wasi_fd_filestat_get(orig_fd, &mut orig_filestat);
+    assert_eq!(
+        status,
+        wasi_unstable::raw::__WASI_ESUCCESS,
+        "reading filestat of the source"
+    );
+    status = wasi_fd_filestat_get(link_fd, &mut link_filestat);
+    assert_eq!(
+        status,
+        wasi_unstable::raw::__WASI_ESUCCESS,
+        "reading filestat of the link"
+    );
+    assert_eq!(orig_filestat, link_filestat, "filestats should match");
+
+    // Compare FdStats
+    let mut orig_fdstat: wasi_unstable::FdStat = MaybeUninit::zeroed().assume_init();
+    let mut link_fdstat: wasi_unstable::FdStat = MaybeUninit::zeroed().assume_init();
+    status = wasi_fd_fdstat_get(orig_fd, &mut orig_fdstat);
+    assert_eq!(
+        status,
+        wasi_unstable::raw::__WASI_ESUCCESS,
+        "reading fdstat of the source"
+    );
+    status = wasi_fd_fdstat_get(link_fd, &mut link_fdstat);
+    assert_eq!(
+        status,
+        wasi_unstable::raw::__WASI_ESUCCESS,
+        "reading fdstat of the link"
+    );
+    assert_eq!(orig_fdstat, link_fdstat, "fdstats should match");
+}
+
+unsafe fn test_path_link(dir_fd: wasi_unstable::Fd) {
+    // Create a file
+    let file_fd = create_or_open(dir_fd, "file", wasi_unstable::O_CREAT);
+
+    // Create a link in the same directory and compare rights
+    assert!(
+        wasi_path_link(dir_fd, 0, "file", dir_fd, "link").is_ok(),
+        "creating a link in the same directory"
+    );
+    let mut link_fd = open_link(dir_fd, "link");
+    check_rights(file_fd, link_fd);
+    cleanup_file(dir_fd, "link");
+
+    // Create a link in a different directory and compare rights
+    create_dir(dir_fd, "subdir");
+    let subdir_fd = create_or_open(dir_fd, "subdir", wasi_unstable::O_DIRECTORY);
+    assert!(
+        wasi_path_link(dir_fd, 0, "file", subdir_fd, "link").is_ok(),
+        "creating a link in subdirectory"
+    );
+    link_fd = open_link(subdir_fd, "link");
+    check_rights(file_fd, link_fd);
+    cleanup_file(subdir_fd, "link");
+    cleanup_dir(dir_fd, "subdir");
+
+    // Create a link to a path that already exists
+    create_file(dir_fd, "link");
+    assert_eq!(
+        wasi_path_link(dir_fd, 0, "file", dir_fd, "link"),
+        Err(wasi_unstable::EEXIST),
+        "creating a link to existing path"
+    );
+    cleanup_file(dir_fd, "link");
+
+    // Create a link to itself
+    assert_eq!(
+        wasi_path_link(dir_fd, 0, "file", dir_fd, "file"),
+        Err(wasi_unstable::EEXIST),
+        "creating a link to itself"
+    );
+
+    // Create a link where target is a directory
+    create_dir(dir_fd, "link");
+    assert_eq!(
+        wasi_path_link(dir_fd, 0, "file", dir_fd, "link"),
+        Err(wasi_unstable::EEXIST),
+        "creating a link where target is a directory"
+    );
+    cleanup_dir(dir_fd, "link");
+
+    // Create a link to a directory
+    create_dir(dir_fd, "subdir");
+    let subdir_fd = create_or_open(dir_fd, "subdir", wasi_unstable::O_DIRECTORY);
+    assert_eq!(
+        wasi_path_link(dir_fd, 0, "subdir", dir_fd, "link"),
+        Err(wasi_unstable::EPERM),
+        "creating a link to a directory"
+    );
+    cleanup_dir(dir_fd, "subdir");
+
+    // Create a link to a file with trailing slash
+    assert_eq!(
+        wasi_path_link(dir_fd, 0, "file", dir_fd, "link/"),
+        Err(wasi_unstable::ENOENT),
+        "creating a link to a file with trailing slash"
+    );
+
+    // Create a link to a dangling symlink
+    assert!(
+        wasi_path_symlink("target", dir_fd, "symlink").is_ok(),
+        "creating a dangling symlink"
+    );
+    assert_eq!(
+        wasi_path_link(dir_fd, 0, "symlink", dir_fd, "link"),
+        Err(wasi_unstable::ENOENT),
+        "creating a link to a dangling symlink"
+    );
+    cleanup_file(dir_fd, "symlink");
+
+    // Create a link to a symlink loop
+    assert!(
+        wasi_path_symlink("symlink", dir_fd, "symlink").is_ok(),
+        "creating a symlink loop"
+    );
+    assert_eq!(
+        wasi_path_link(dir_fd, 0, "symlink", dir_fd, "link"),
+        Err(wasi_unstable::ELOOP),
+        "creating a link to a symlink loop"
+    );
+    cleanup_file(dir_fd, "symlink");
+
+    // Create a link where target is a dangling symlink
+    assert!(
+        wasi_path_symlink("target", dir_fd, "symlink").is_ok(),
+        "creating a dangling symlink"
+    );
+    assert_eq!(
+        wasi_path_link(dir_fd, 0, "file", dir_fd, "symlink"),
+        Err(wasi_unstable::EEXIST),
+        "creating a link where target is a dangling symlink"
+    );
+    cleanup_file(dir_fd, "symlink");
+
+    // Create a link to a file following symlinks
+    assert!(
+        wasi_path_symlink("file", dir_fd, "symlink").is_ok(),
+        "creating a valid symlink"
+    );
+    assert!(
+        wasi_path_link(
+            dir_fd,
+            wasi_unstable::LOOKUP_SYMLINK_FOLLOW,
+            "symlink",
+            dir_fd,
+            "link"
+        )
+        .is_ok(),
+        "creating a link to a file following symlinks",
+    );
+    link_fd = open_link(dir_fd, "link");
+    check_rights(file_fd, link_fd);
+    cleanup_file(dir_fd, "link");
+    cleanup_file(dir_fd, "symlink");
+
+    // Create a link where target is a dangling symlink following symlinks
+    assert!(
+        wasi_path_symlink("target", dir_fd, "symlink").is_ok(),
+        "creating a dangling symlink"
+    );
+    assert_eq!(
+        wasi_path_link(
+            dir_fd,
+            wasi_unstable::LOOKUP_SYMLINK_FOLLOW,
+            "symlink",
+            dir_fd,
+            "link"
+        ),
+        Err(wasi_unstable::ENOENT),
+        "creating a link where target is a dangling symlink following symlinks"
+    );
+    cleanup_file(dir_fd, "symlink");
+
+    // Create a link to a symlink loop following symlinks
+    assert!(
+        wasi_path_symlink("symlink", dir_fd, "symlink").is_ok(),
+        "creating a symlink loop"
+    );
+    assert_eq!(
+        wasi_path_link(
+            dir_fd,
+            wasi_unstable::LOOKUP_SYMLINK_FOLLOW,
+            "symlink",
+            dir_fd,
+            "link"
+        ),
+        Err(wasi_unstable::ELOOP),
+        "creating a link to a symlink loop following symlinks"
+    );
+    cleanup_file(dir_fd, "symlink");
+
+    // Clean up.
+    cleanup_file(dir_fd, "file");
+}
+
+fn main() {
+    let mut args = env::args();
+    let prog = args.next().unwrap();
+    let arg = if let Some(arg) = args.next() {
+        arg
+    } else {
+        eprintln!("usage: {} <scratch directory>", prog);
+        process::exit(1);
+    };
+
+    // Open scratch directory
+    let dir_fd = match open_scratch_directory(&arg) {
+        Ok(dir_fd) => dir_fd,
+        Err(err) => {
+            eprintln!("{}", err);
+            process::exit(1)
+        }
+    };
+
+    // Run the tests.
+    unsafe { test_path_link(dir_fd) }
+}

crates/test-programs/wasi-tests/src/bin/path_open_dirfd_not_dir.rs

@@ -0,0 +1,67 @@
+use std::{env, process};
+use wasi::wasi_unstable;
+use wasi_tests::open_scratch_directory;
+use wasi_tests::utils::close_fd;
+use wasi_tests::wasi_wrappers::wasi_path_open;
+
+unsafe fn test_dirfd_not_dir(dir_fd: wasi_unstable::Fd) {
+    // Open a file.
+    let mut file_fd: wasi_unstable::Fd = wasi_unstable::Fd::max_value() - 1;
+    let mut status = wasi_path_open(
+        dir_fd,
+        0,
+        "file",
+        wasi_unstable::O_CREAT,
+        0,
+        0,
+        0,
+        &mut file_fd,
+    );
+    assert_eq!(
+        status,
+        wasi_unstable::raw::__WASI_ESUCCESS,
+        "opening a file"
+    );
+
+    // Now try to open a file underneath it as if it were a directory.
+    let mut new_file_fd: wasi_unstable::Fd = wasi_unstable::Fd::max_value() - 1;
+    status = wasi_path_open(
+        file_fd,
+        0,
+        "foo",
+        wasi_unstable::O_CREAT,
+        0,
+        0,
+        0,
+        &mut new_file_fd,
+    );
+    assert_eq!(
+        status,
+        wasi_unstable::raw::__WASI_ENOTDIR,
+        "non-directory base fd should get ENOTDIR"
+    );
+    close_fd(file_fd);
+}
+
+fn main() {
+    let mut args = env::args();
+    let prog = args.next().unwrap();
+    let arg = if let Some(arg) = args.next() {
+        arg
+    } else {
+        eprintln!("usage: {} <scratch directory>", prog);
+        process::exit(1);
+    };
+
+    // Open scratch directory
+    let dir_fd = match open_scratch_directory(&arg) {
+        Ok(dir_fd) => dir_fd,
+        Err(err) => {
+            eprintln!("{}", err);
+            process::exit(1)
+        }
+    };
+
+    // Run the tests.
+    unsafe { test_dirfd_not_dir(dir_fd) }
+}

crates/test-programs/wasi-tests/src/bin/path_rename.rs

@@ -0,0 +1,258 @@
+use more_asserts::assert_gt;
+use std::{env, process};
+use wasi::wasi_unstable;
+use wasi_tests::open_scratch_directory;
+use wasi_tests::utils::{cleanup_dir, cleanup_file, close_fd, create_dir, create_file};
+use wasi_tests::wasi_wrappers::{wasi_path_open, wasi_path_rename};
+
+unsafe fn test_path_rename(dir_fd: wasi_unstable::Fd) {
+    // First, try renaming a dir to nonexistent path
+    // Create source directory
+    create_dir(dir_fd, "source");
+
+    // Try renaming the directory
+    assert!(
+        wasi_path_rename(dir_fd, "source", dir_fd, "target").is_ok(),
+        "renaming a directory"
+    );
+
+    // Check that source directory doesn't exist anymore
+    let mut fd: wasi_unstable::Fd = wasi_unstable::Fd::max_value() - 1;
+    let mut status = wasi_path_open(
+        dir_fd,
+        0,
+        "source",
+        wasi_unstable::O_DIRECTORY,
+        0,
+        0,
+        0,
+        &mut fd,
+    );
+    assert_eq!(
+        status,
+        wasi_unstable::raw::__WASI_ENOENT,
+        "opening a nonexistent path as a directory"
+    );
+    assert_eq!(
+        fd,
+        wasi_unstable::Fd::max_value(),
+        "failed open should set the file descriptor to -1",
+    );
+
+    // Check that target directory exists
+    status = wasi_path_open(
+        dir_fd,
+        0,
+        "target",
+        wasi_unstable::O_DIRECTORY,
+        0,
+        0,
+        0,
+        &mut fd,
+    );
+    assert_eq!(
+        status,
+        wasi_unstable::raw::__WASI_ESUCCESS,
+        "opening renamed path as a directory"
+    );
+    assert_gt!(
+        fd,
+        libc::STDERR_FILENO as wasi_unstable::Fd,
+        "file descriptor range check",
+    );
+
+    close_fd(fd);
+    cleanup_dir(dir_fd, "target");
+
+    // Now, try renaming renaming a dir to existing empty dir
+    create_dir(dir_fd, "source");
+    create_dir(dir_fd, "target");
+
+    assert!(
+        wasi_path_rename(dir_fd, "source", dir_fd, "target").is_ok(),
+        "renaming a directory"
+    );
+
+    // Check that source directory doesn't exist anymore
+    fd = wasi_unstable::Fd::max_value() - 1;
+    status = wasi_path_open(
+        dir_fd,
+        0,
+        "source",
+        wasi_unstable::O_DIRECTORY,
+        0,
+        0,
+        0,
+        &mut fd,
+    );
+    assert_eq!(
+        status,
+        wasi_unstable::raw::__WASI_ENOENT,
+        "opening a nonexistent path as a directory"
+    );
+    assert_eq!(
+        fd,
+        wasi_unstable::Fd::max_value(),
+        "failed open should set the file descriptor to -1",
+    );
+
+    // Check that target directory exists
+    status = wasi_path_open(
+        dir_fd,
+        0,
+        "target",
+        wasi_unstable::O_DIRECTORY,
+        0,
+        0,
+        0,
+        &mut fd,
+    );
+    assert_eq!(
+        status,
+        wasi_unstable::raw::__WASI_ESUCCESS,
+        "opening renamed path as a directory"
+    );
+    assert_gt!(
+        fd,
+        libc::STDERR_FILENO as wasi_unstable::Fd,
+        "file descriptor range check",
+    );
+
+    close_fd(fd);
+    cleanup_dir(dir_fd, "target");
+
+    // Now, try renaming a dir to existing non-empty dir
+    create_dir(dir_fd, "source");
+    create_dir(dir_fd, "target");
+    create_file(dir_fd, "target/file");
+
+    assert_eq!(
+        wasi_path_rename(dir_fd, "source", dir_fd, "target"),
+        Err(wasi_unstable::ENOTEMPTY),
+        "renaming directory to a nonempty directory"
+    );
+
+    // Try renaming dir to a file
+    assert_eq!(
+        wasi_path_rename(dir_fd, "source", dir_fd, "target/file"),
+        Err(wasi_unstable::ENOTDIR),
+        "renaming directory to a file"
+    );
+
+    cleanup_file(dir_fd, "target/file");
+    cleanup_dir(dir_fd, "target");
+    cleanup_dir(dir_fd, "source");
+
+    // Now, try renaming a file to a nonexistent path
+    create_file(dir_fd, "source");
+
+    assert!(
+        wasi_path_rename(dir_fd, "source", dir_fd, "target").is_ok(),
+        "renaming a file"
+    );
+
+    // Check that source file doesn't exist anymore
+    fd = wasi_unstable::Fd::max_value() - 1;
+    status = wasi_path_open(dir_fd, 0, "source", 0, 0, 0, 0, &mut fd);
+    assert_eq!(
+        status,
+        wasi_unstable::raw::__WASI_ENOENT,
+        "opening a nonexistent path"
+    );
+    assert_eq!(
+        fd,
+        wasi_unstable::Fd::max_value(),
+        "failed open should set the file descriptor to -1",
+    );
+
+    // Check that target file exists
+    status = wasi_path_open(dir_fd, 0, "target", 0, 0, 0, 0, &mut fd);
+    assert_eq!(
+        status,
+        wasi_unstable::raw::__WASI_ESUCCESS,
+        "opening renamed path"
+    );
+    assert_gt!(
+        fd,
+        libc::STDERR_FILENO as wasi_unstable::Fd,
+        "file descriptor range check",
+    );
+
+    close_fd(fd);
+    cleanup_file(dir_fd, "target");
+
+    // Now, try renaming file to an existing file
+    create_file(dir_fd, "source");
+    create_file(dir_fd, "target");
+
+    assert!(
+        wasi_path_rename(dir_fd, "source", dir_fd, "target").is_ok(),
+        "renaming file to another existing file"
+    );
+
+    // Check that source file doesn't exist anymore
+    fd = wasi_unstable::Fd::max_value() - 1;
+    status = wasi_path_open(dir_fd, 0, "source", 0, 0, 0, 0, &mut fd);
+    assert_eq!(
+        status,
+        wasi_unstable::raw::__WASI_ENOENT,
+        "opening a nonexistent path"
+    );
+    assert_eq!(
+        fd,
+        wasi_unstable::Fd::max_value(),
+        "failed open should set the file descriptor to -1",
+    );
+
+    // Check that target file exists
+    status = wasi_path_open(dir_fd, 0, "target", 0, 0, 0, 0, &mut fd);
+    assert_eq!(
+        status,
+        wasi_unstable::raw::__WASI_ESUCCESS,
+        "opening renamed path"
+    );
+    assert_gt!(
+        fd,
+        libc::STDERR_FILENO as wasi_unstable::Fd,
+        "file descriptor range check",
+    );
+
+    close_fd(fd);
+    cleanup_file(dir_fd, "target");
+
+    // Try renaming to an (empty) directory instead
+    create_file(dir_fd, "source");
+    create_dir(dir_fd, "target");
+
+    assert_eq!(
+        wasi_path_rename(dir_fd, "source", dir_fd, "target"),
+        Err(wasi_unstable::EISDIR),
+        "renaming file to existing directory"
+    );
+
+    cleanup_dir(dir_fd, "target");
+    cleanup_file(dir_fd, "source");
+}
+
+fn main() {
+    let mut args = env::args();
+    let prog = args.next().unwrap();
+    let arg = if let Some(arg) = args.next() {
+        arg
+    } else {
+        eprintln!("usage: {} <scratch directory>", prog);
+        process::exit(1);
+    };
+
+    // Open scratch directory
+    let dir_fd = match open_scratch_directory(&arg) {
+        Ok(dir_fd) => dir_fd,
+        Err(err) => {
+            eprintln!("{}", err);
+            process::exit(1)
+        }
+    };
+
+    // Run the tests.
+    unsafe { test_path_rename(dir_fd) }
+}

crates/test-programs/wasi-tests/src/bin/path_rename_trailing_slashes.rs

@@ -0,0 +1,68 @@
+use std::{env, process};
+use wasi::wasi_unstable;
+use wasi_tests::open_scratch_directory;
+use wasi_tests::utils::{cleanup_dir, cleanup_file, create_dir, create_file};
+use wasi_tests::wasi_wrappers::wasi_path_rename;
+
+unsafe fn test_path_rename_trailing_slashes(dir_fd: wasi_unstable::Fd) {
+    // Test renaming a file with a trailing slash in the name.
+    create_file(dir_fd, "source");
+    assert_eq!(
+        wasi_path_rename(dir_fd, "source/", dir_fd, "target"),
+        Err(wasi_unstable::ENOTDIR),
+        "renaming a file with a trailing slash in the source name"
+    );
+    assert_eq!(
+        wasi_path_rename(dir_fd, "source", dir_fd, "target/"),
+        Err(wasi_unstable::ENOTDIR),
+        "renaming a file with a trailing slash in the destination name"
+    );
+    assert_eq!(
+        wasi_path_rename(dir_fd, "source/", dir_fd, "target/"),
+        Err(wasi_unstable::ENOTDIR),
+        "renaming a file with a trailing slash in the source and destination names"
+    );
+    cleanup_file(dir_fd, "source");
+
+    // Test renaming a directory with a trailing slash in the name.
+    create_dir(dir_fd, "source");
+    assert_eq!(
+        wasi_path_rename(dir_fd, "source/", dir_fd, "target"),
+        Ok(()),
+        "renaming a directory with a trailing slash in the source name"
+    );
+    assert_eq!(
+        wasi_path_rename(dir_fd, "target", dir_fd, "source/"),
+        Ok(()),
+        "renaming a directory with a trailing slash in the destination name"
+    );
+    assert_eq!(
+        wasi_path_rename(dir_fd, "source/", dir_fd, "target/"),
+        Ok(()),
+        "renaming a directory with a trailing slash in the source and destination names"
+    );
+    cleanup_dir(dir_fd, "target");
+}
+
+fn main() {
+    let mut args = env::args();
+    let prog = args.next().unwrap();
+    let arg = if let Some(arg) = args.next() {
+        arg
+    } else {
+        eprintln!("usage: {} <scratch directory>", prog);
+        process::exit(1);
+    };
+
+    // Open scratch directory
+    let dir_fd = match open_scratch_directory(&arg) {
+        Ok(dir_fd) => dir_fd,
+        Err(err) => {
+            eprintln!("{}", err);
+            process::exit(1)
+        }
+    };
+
+    // Run the tests.
+    unsafe { test_path_rename_trailing_slashes(dir_fd) }
+}

crates/test-programs/wasi-tests/src/bin/path_symlink_trailing_slashes.rs

@@ -0,0 +1,81 @@
+use std::{env, process};
+use wasi::wasi_unstable;
+use wasi_tests::open_scratch_directory;
+use wasi_tests::utils::{cleanup_dir, cleanup_file, create_dir, create_file};
+use wasi_tests::wasi_wrappers::wasi_path_symlink;
+
+unsafe fn test_path_symlink_trailing_slashes(dir_fd: wasi_unstable::Fd) {
+    // Link destination shouldn't end with a slash.
+    assert_eq!(
+        wasi_path_symlink("source", dir_fd, "target/"),
+        Err(wasi_unstable::ENOENT),
+        "link destination ending with a slash"
+    );
+
+    // Without the trailing slash, this should succeed.
+    assert_eq!(
+        wasi_path_symlink("source", dir_fd, "target"),
+        Ok(()),
+        "link destination ending with a slash"
+    );
+    cleanup_file(dir_fd, "target");
+
+    // Link destination already exists, target has trailing slash.
+    create_dir(dir_fd, "target");
+    assert_eq!(
+        wasi_path_symlink("source", dir_fd, "target/"),
+        Err(wasi_unstable::EEXIST),
+        "link destination already exists"
+    );
+    cleanup_dir(dir_fd, "target");
+
+    // Link destination already exists, target has no trailing slash.
+    create_dir(dir_fd, "target");
+    assert_eq!(
+        wasi_path_symlink("source", dir_fd, "target"),
+        Err(wasi_unstable::EEXIST),
+        "link destination already exists"
+    );
+    cleanup_dir(dir_fd, "target");
+
+    // Link destination already exists, target has trailing slash.
+    create_file(dir_fd, "target");
+    assert_eq!(
+        wasi_path_symlink("source", dir_fd, "target/"),
+        Err(wasi_unstable::EEXIST),
+        "link destination already exists"
+    );
+    cleanup_file(dir_fd, "target");
+
+    // Link destination already exists, target has no trailing slash.
+    create_file(dir_fd, "target");
+    assert_eq!(
+        wasi_path_symlink("source", dir_fd, "target"),
+        Err(wasi_unstable::EEXIST),
+        "link destination already exists"
+    );
+    cleanup_file(dir_fd, "target");
+}
+
+fn main() {
+    let mut args = env::args();
+    let prog = args.next().unwrap();
+    let arg = if let Some(arg) = args.next() {
+        arg
+    } else {
+        eprintln!("usage: {} <scratch directory>", prog);
+        process::exit(1);
+    };
+
+    // Open scratch directory
+    let dir_fd = match open_scratch_directory(&arg) {
+        Ok(dir_fd) => dir_fd,
+        Err(err) => {
+            eprintln!("{}", err);
+            process::exit(1)
+        }
+    };
+
+    // Run the tests.
+    unsafe { test_path_symlink_trailing_slashes(dir_fd) }
+}

crates/test-programs/wasi-tests/src/bin/poll_oneoff.rs

@@ -0,0 +1,270 @@
+use more_asserts::assert_gt;
+use std::{env, mem::MaybeUninit, process};
+use wasi::wasi_unstable;
+use wasi_tests::{
+    open_scratch_directory,
+    utils::{cleanup_file, close_fd},
+    wasi_wrappers::wasi_path_open,
+};
+
+const CLOCK_ID: wasi_unstable::Userdata = 0x0123_45678;
+
+unsafe fn poll_oneoff_impl(
+    in_: &[wasi_unstable::Subscription],
+    nexpected: usize,
+) -> Vec<wasi_unstable::Event> {
+    let mut out: Vec<wasi_unstable::Event> = Vec::new();
+    out.resize_with(in_.len(), || {
+        MaybeUninit::<wasi_unstable::Event>::zeroed().assume_init()
+    });
+    let res = wasi_unstable::poll_oneoff(&in_, out.as_mut_slice());
+    let res = res.expect("poll_oneoff should succeed");
+    assert_eq!(
+        res, nexpected,
+        "poll_oneoff should return {} events",
+        nexpected
+    );
+    out
+}
+
+unsafe fn test_timeout() {
+    let clock = wasi_unstable::raw::__wasi_subscription_u_clock_t {
+        identifier: CLOCK_ID,
+        clock_id: wasi_unstable::CLOCK_MONOTONIC,
+        timeout: 5_000_000u64, // 5 milliseconds
+        precision: 0,
+        flags: 0,
+    };
+    let in_ = [wasi_unstable::Subscription {
+        userdata: CLOCK_ID,
+        type_: wasi_unstable::EVENTTYPE_CLOCK,
+        u: wasi_unstable::raw::__wasi_subscription_u { clock },
+    }];
+    let out = poll_oneoff_impl(&in_, 1);
+    let event = &out[0];
+    assert_eq!(
+        event.userdata, CLOCK_ID,
+        "the event.userdata should contain clock_id specified by the user"
+    );
+    assert_eq!(
+        event.error,
+        wasi_unstable::raw::__WASI_ESUCCESS,
+        "the event.error should be set to ESUCCESS"
+    );
+    assert_eq!(
+        event.type_,
+        wasi_unstable::EVENTTYPE_CLOCK,
+        "the event.type_ should equal clock"
+    );
+}
+
+unsafe fn test_stdin_read() {
+    let clock = wasi_unstable::raw::__wasi_subscription_u_clock_t {
+        identifier: CLOCK_ID,
+        clock_id: wasi_unstable::CLOCK_MONOTONIC,
+        timeout: 5_000_000u64, // 5 milliseconds
+        precision: 0,
+        flags: 0,
+    };
+    let fd_readwrite = wasi_unstable::raw::__wasi_subscription_u_fd_readwrite_t {
+        fd: wasi_unstable::STDIN_FD,
+    };
+    let in_ = [
+        wasi_unstable::Subscription {
+            userdata: CLOCK_ID,
+            type_: wasi_unstable::EVENTTYPE_CLOCK,
+            u: wasi_unstable::raw::__wasi_subscription_u { clock },
+        },
+        wasi_unstable::Subscription {
+            userdata: 1,
+            type_: wasi_unstable::EVENTTYPE_FD_READ,
+            u: wasi_unstable::raw::__wasi_subscription_u { fd_readwrite },
+        },
+    ];
+    let out = poll_oneoff_impl(&in_, 1);
+    let event = &out[0];
+    assert_eq!(
+        event.userdata, CLOCK_ID,
+        "the event.userdata should contain clock_id specified by the user"
+    );
+    assert_eq!(
+        event.error,
+        wasi_unstable::raw::__WASI_ESUCCESS,
+        "the event.error should be set to ESUCCESS"
+    );
+    assert_eq!(
+        event.type_,
+        wasi_unstable::EVENTTYPE_CLOCK,
+        "the event.type_ should equal clock"
+    );
+}
+
+unsafe fn test_stdout_stderr_write() {
+    let stdout_readwrite = wasi_unstable::raw::__wasi_subscription_u_fd_readwrite_t {
+        fd: wasi_unstable::STDOUT_FD,
+    };
+    let stderr_readwrite = wasi_unstable::raw::__wasi_subscription_u_fd_readwrite_t {
+        fd: wasi_unstable::STDERR_FD,
+    };
+    let in_ = [
+        wasi_unstable::Subscription {
+            userdata: 1,
+            type_: wasi_unstable::EVENTTYPE_FD_WRITE,
+            u: wasi_unstable::raw::__wasi_subscription_u {
+                fd_readwrite: stdout_readwrite,
+            },
+        },
+        wasi_unstable::Subscription {
+            userdata: 2,
+            type_: wasi_unstable::EVENTTYPE_FD_WRITE,
+            u: wasi_unstable::raw::__wasi_subscription_u {
+                fd_readwrite: stderr_readwrite,
+            },
+        },
+    ];
+    let out = poll_oneoff_impl(&in_, 2);
+    assert_eq!(
+        out[0].userdata, 1,
+        "the event.userdata should contain fd userdata specified by the user"
+    );
+    assert_eq!(
+        out[0].error,
+        wasi_unstable::raw::__WASI_ESUCCESS,
+        "the event.error should be set to {}",
+        wasi_unstable::raw::__WASI_ESUCCESS
+    );
+    assert_eq!(
+        out[0].type_,
+        wasi_unstable::EVENTTYPE_FD_WRITE,
+        "the event.type_ should equal FD_WRITE"
+    );
+    assert_eq!(
+        out[1].userdata, 2,
+        "the event.userdata should contain fd userdata specified by the user"
+    );
+    assert_eq!(
+        out[1].error,
+        wasi_unstable::raw::__WASI_ESUCCESS,
+        "the event.error should be set to {}",
+        wasi_unstable::raw::__WASI_ESUCCESS
+    );
+    assert_eq!(
+        out[1].type_,
+        wasi_unstable::EVENTTYPE_FD_WRITE,
+        "the event.type_ should equal FD_WRITE"
+    );
+}
+
+unsafe fn test_fd_readwrite(fd: wasi_unstable::Fd, error_code: wasi_unstable::raw::__wasi_errno_t) {
+    let fd_readwrite = wasi_unstable::raw::__wasi_subscription_u_fd_readwrite_t { fd };
+    let in_ = [
+        wasi_unstable::Subscription {
+            userdata: 1,
+            type_: wasi_unstable::EVENTTYPE_FD_READ,
+            u: wasi_unstable::raw::__wasi_subscription_u { fd_readwrite },
+        },
+        wasi_unstable::Subscription {
+            userdata: 2,
+            type_: wasi_unstable::EVENTTYPE_FD_WRITE,
+            u: wasi_unstable::raw::__wasi_subscription_u { fd_readwrite },
+        },
+    ];
+    let out = poll_oneoff_impl(&in_, 2);
+    assert_eq!(
+        out[0].userdata, 1,
+        "the event.userdata should contain fd userdata specified by the user"
+    );
+    assert_eq!(
+        out[0].error, error_code,
+        "the event.error should be set to {}",
+        error_code
+    );
+    assert_eq!(
+        out[0].type_,
+        wasi_unstable::EVENTTYPE_FD_READ,
+        "the event.type_ should equal FD_READ"
+    );
+    assert_eq!(
+        out[1].userdata, 2,
+        "the event.userdata should contain fd userdata specified by the user"
+    );
+    assert_eq!(
+        out[1].error, error_code,
+        "the event.error should be set to {}",
+        error_code
+    );
+    assert_eq!(
+        out[1].type_,
+        wasi_unstable::EVENTTYPE_FD_WRITE,
+        "the event.type_ should equal FD_WRITE"
+    );
+}
+
+unsafe fn test_fd_readwrite_valid_fd(dir_fd: wasi_unstable::Fd) {
+    // Create a file in the scratch directory.
+    let mut file_fd = wasi_unstable::Fd::max_value() - 1;
+    let status = wasi_path_open(
+        dir_fd,
+        0,
+        "file",
+        wasi_unstable::O_CREAT,
+        wasi_unstable::RIGHT_FD_READ | wasi_unstable::RIGHT_FD_WRITE,
+        0,
+        0,
+        &mut file_fd,
+    );
+    assert_eq!(
+        status,
+        wasi_unstable::raw::__WASI_ESUCCESS,
+        "opening a file"
+    );
+    assert_gt!(
+        file_fd,
+        libc::STDERR_FILENO as wasi_unstable::Fd,
+        "file descriptor range check",
+    );
+
+    test_fd_readwrite(file_fd, wasi_unstable::raw::__WASI_ESUCCESS);
+
+    close_fd(file_fd);
+    cleanup_file(dir_fd, "file");
+}
+
+unsafe fn test_fd_readwrite_invalid_fd() {
+    test_fd_readwrite(
+        wasi_unstable::Fd::max_value(),
+        wasi_unstable::raw::__WASI_EBADF,
+    )
+}
+
+unsafe fn test_poll_oneoff(dir_fd: wasi_unstable::Fd) {
+    test_timeout();
+    // NB we assume that stdin/stdout/stderr are valid and open
+    // for the duration of the test case
+    test_stdin_read();
+    test_stdout_stderr_write();
+    test_fd_readwrite_valid_fd(dir_fd);
+    test_fd_readwrite_invalid_fd();
+}
+fn main() {
+    let mut args = env::args();
+    let prog = args.next().unwrap();
+    let arg = if let Some(arg) = args.next() {
+        arg
+    } else {
+        eprintln!("usage: {} <scratch directory>", prog);
+        process::exit(1);
+    };
+
+    // Open scratch directory
+    let dir_fd = match open_scratch_directory(&arg) {
+        Ok(dir_fd) => dir_fd,
+        Err(err) => {
+            eprintln!("{}", err);
+            process::exit(1)
+        }
+    };
+
+    // Run the tests.
+    unsafe { test_poll_oneoff(dir_fd) }
+}

crates/test-programs/wasi-tests/src/bin/readlink.rs

@@ -0,0 +1,72 @@
+use std::{env, process};
+use wasi::wasi_unstable;
+use wasi_tests::open_scratch_directory;
+use wasi_tests::utils::{cleanup_file, create_file};
+use wasi_tests::wasi_wrappers::{wasi_path_readlink, wasi_path_symlink};
+
+unsafe fn test_readlink(dir_fd: wasi_unstable::Fd) {
+    // Create a file in the scratch directory.
+    create_file(dir_fd, "target");
+
+    // Create a symlink
+    assert!(
+        wasi_path_symlink("target", dir_fd, "symlink").is_ok(),
+        "creating a symlink"
+    );
+
+    // Read link into the buffer
+    let buf = &mut [0u8; 10];
+    let mut bufused: usize = 0;
+    let mut status = wasi_path_readlink(dir_fd, "symlink", buf, &mut bufused);
+    assert_eq!(
+        status,
+        wasi_unstable::raw::__WASI_ESUCCESS,
+        "readlink should succeed"
+    );
+    assert_eq!(bufused, 6, "should use 6 bytes of the buffer");
+    assert_eq!(&buf[..6], b"target", "buffer should contain 'target'");
+    assert_eq!(
+        &buf[6..],
+        &[0u8; 4],
+        "the remaining bytes should be untouched"
+    );
+
+    // Read link into smaller buffer than the actual link's length
+    let buf = &mut [0u8; 4];
+    let mut bufused: usize = 0;
+    status = wasi_path_readlink(dir_fd, "symlink", buf, &mut bufused);
+    assert_eq!(
+        status,
+        wasi_unstable::raw::__WASI_ESUCCESS,
+        "readlink should succeed"
+    );
+    assert_eq!(bufused, 4, "should use all 4 bytes of the buffer");
+    assert_eq!(buf, b"targ", "buffer should contain 'targ'");
+
+    // Clean up.
+    cleanup_file(dir_fd, "target");
+    cleanup_file(dir_fd, "symlink");
+}
+
+fn main() {
+    let mut args = env::args();
+    let prog = args.next().unwrap();
+    let arg = if let Some(arg) = args.next() {
+        arg
+    } else {
+        eprintln!("usage: {} <scratch directory>", prog);
+        process::exit(1);
+    };
+
+    // Open scratch directory
+    let dir_fd = match open_scratch_directory(&arg) {
+        Ok(dir_fd) => dir_fd,
+        Err(err) => {
+            eprintln!("{}", err);
+            process::exit(1)
+        }
+    };
+
+    // Run the tests.
+    unsafe { test_readlink(dir_fd) }
+}

crates/test-programs/wasi-tests/src/bin/readlink_no_buffer.rs

@@ -0,0 +1,51 @@
+use std::{env, process};
+use wasi::wasi_unstable;
+use wasi_tests::open_scratch_directory;
+use wasi_tests::utils::cleanup_file;
+use wasi_tests::wasi_wrappers::{wasi_path_readlink, wasi_path_symlink};
+
+unsafe fn test_readlink_no_buffer(dir_fd: wasi_unstable::Fd) {
+    // First create a dangling symlink.
+    assert!(
+        wasi_path_symlink("target", dir_fd, "symlink").is_ok(),
+        "creating a symlink"
+    );
+
+    // Readlink it into a non-existent buffer.
+    let mut bufused: usize = 1;
+    let status = wasi_path_readlink(dir_fd, "symlink", &mut [], &mut bufused);
+    assert_eq!(
+        status,
+        wasi_unstable::raw::__WASI_ESUCCESS,
+        "readlink with a 0-sized buffer should succeed"
+    );
+    assert_eq!(
+        bufused, 0,
+        "readlink with a 0-sized buffer should return 'bufused' 0"
+    );
+
+    // Clean up.
+    cleanup_file(dir_fd, "symlink");
+}
+fn main() {
+    let mut args = env::args();
+    let prog = args.next().unwrap();
+    let arg = if let Some(arg) = args.next() {
+        arg
+    } else {
+        eprintln!("usage: {} <scratch directory>", prog);
+        process::exit(1);
+    };
+
+    // Open scratch directory
+    let dir_fd = match open_scratch_directory(&arg) {
+        Ok(dir_fd) => dir_fd,
+        Err(err) => {
+            eprintln!("{}", err);
+            process::exit(1)
+        }
+    };
+
+    // Run the tests.
+    unsafe { test_readlink_no_buffer(dir_fd) }
+}

crates/test-programs/wasi-tests/src/bin/remove_directory_trailing_slashes.rs

@@ -0,0 +1,68 @@
+use std::{env, process};
+use wasi::wasi_unstable;
+use wasi_tests::open_scratch_directory;
+use wasi_tests::utils::{cleanup_file, create_dir, create_file};
+use wasi_tests::wasi_wrappers::wasi_path_remove_directory;
+
+unsafe fn test_remove_directory_trailing_slashes(dir_fd: wasi_unstable::Fd) {
+    // Create a directory in the scratch directory.
+    create_dir(dir_fd, "dir");
+
+    // Test that removing it succeeds.
+    assert_eq!(
+        wasi_path_remove_directory(dir_fd, "dir"),
+        Ok(()),
+        "remove_directory on a directory should succeed"
+    );
+
+    create_dir(dir_fd, "dir");
+
+    // Test that removing it with a trailing flash succeeds.
+    assert_eq!(
+        wasi_path_remove_directory(dir_fd, "dir/"),
+        Ok(()),
+        "remove_directory with a trailing slash on a directory should succeed"
+    );
+
+    // Create a temporary file.
+    create_file(dir_fd, "file");
+
+    // Test that removing it with no trailing flash fails.
+    assert_eq!(
+        wasi_path_remove_directory(dir_fd, "file"),
+        Err(wasi_unstable::ENOTDIR),
+        "remove_directory without a trailing slash on a file should fail"
+    );
+
+    // Test that removing it with a trailing flash fails.
+    assert_eq!(
+        wasi_path_remove_directory(dir_fd, "file/"),
+        Err(wasi_unstable::ENOTDIR),
+        "remove_directory with a trailing slash on a file should fail"
+    );
+
+    cleanup_file(dir_fd, "file");
+}
+
+fn main() {
+    let mut args = env::args();
+    let prog = args.next().unwrap();
+    let arg = if let Some(arg) = args.next() {
+        arg
+    } else {
+        eprintln!("usage: {} <scratch directory>", prog);
+        process::exit(1);
+    };
+
+    // Open scratch directory
+    let dir_fd = match open_scratch_directory(&arg) {
+        Ok(dir_fd) => dir_fd,
+        Err(err) => {
+            eprintln!("{}", err);
+            process::exit(1)
+        }
+    };
+
+    // Run the tests.
+    unsafe { test_remove_directory_trailing_slashes(dir_fd) }
+}

crates/test-programs/wasi-tests/src/bin/remove_nonempty_directory.rs

@@ -0,0 +1,50 @@
+use std::{env, process};
+use wasi::wasi_unstable;
+use wasi_tests::open_scratch_directory;
+use wasi_tests::utils::{cleanup_dir, create_dir};
+use wasi_tests::wasi_wrappers::wasi_path_remove_directory;
+
+unsafe fn test_remove_nonempty_directory(dir_fd: wasi_unstable::Fd) {
+    // Create a directory in the scratch directory.
+    create_dir(dir_fd, "dir");
+
+    // Create a directory in the directory we just created.
+    create_dir(dir_fd, "dir/nested");
+
+    // Test that attempting to unlink the first directory returns the expected error code.
+    assert_eq!(
+        wasi_path_remove_directory(dir_fd, "dir"),
+        Err(wasi_unstable::ENOTEMPTY),
+        "remove_directory on a directory should return ENOTEMPTY",
+    );
+
+    // Removing the directories.
+    assert!(
+        wasi_path_remove_directory(dir_fd, "dir/nested").is_ok(),
+        "remove_directory on a nested directory should succeed",
+    );
+    cleanup_dir(dir_fd, "dir");
+}
+
+fn main() {
+    let mut args = env::args();
+    let prog = args.next().unwrap();
+    let arg = if let Some(arg) = args.next() {
+        arg
+    } else {
+        eprintln!("usage: {} <scratch directory>", prog);
+        process::exit(1);
+    };
+
+    // Open scratch directory
+    let dir_fd = match open_scratch_directory(&arg) {
+        Ok(dir_fd) => dir_fd,
+        Err(err) => {
+            eprintln!("{}", err);
+            process::exit(1)
+        }
+    };
+
+    // Run the tests.
+    unsafe { test_remove_nonempty_directory(dir_fd) }
+}

crates/test-programs/wasi-tests/src/bin/renumber.rs

@@ -0,0 +1,131 @@
+use libc;
+use more_asserts::assert_gt;
+use std::{env, mem, process};
+use wasi::wasi_unstable;
+use wasi_tests::open_scratch_directory;
+use wasi_tests::utils::close_fd;
+use wasi_tests::wasi_wrappers::{wasi_fd_fdstat_get, wasi_path_open};
+
+unsafe fn test_renumber(dir_fd: wasi_unstable::Fd) {
+    let pre_fd: wasi_unstable::Fd = (libc::STDERR_FILENO + 1) as wasi_unstable::Fd;
+
+    assert_gt!(dir_fd, pre_fd, "dir_fd number");
+
+    // Create a file in the scratch directory.
+    let mut fd_from = wasi_unstable::Fd::max_value() - 1;
+    let mut status = wasi_path_open(
+        dir_fd,
+        0,
+        "file1",
+        wasi_unstable::O_CREAT,
+        wasi_unstable::RIGHT_FD_READ | wasi_unstable::RIGHT_FD_WRITE,
+        0,
+        0,
+        &mut fd_from,
+    );
+    assert_eq!(
+        status,
+        wasi_unstable::raw::__WASI_ESUCCESS,
+        "opening a file"
+    );
+    assert_gt!(
+        fd_from,
+        libc::STDERR_FILENO as wasi_unstable::Fd,
+        "file descriptor range check",
+    );
+
+    // Get fd_from fdstat attributes
+    let mut fdstat_from: wasi_unstable::FdStat = mem::zeroed();
+    status = wasi_fd_fdstat_get(fd_from, &mut fdstat_from);
+    assert_eq!(
+        status,
+        wasi_unstable::raw::__WASI_ESUCCESS,
+        "calling fd_fdstat on the open file descriptor"
+    );
+
+    // Create another file in the scratch directory.
+    let mut fd_to = wasi_unstable::Fd::max_value() - 1;
+    status = wasi_path_open(
+        dir_fd,
+        0,
+        "file2",
+        wasi_unstable::O_CREAT,
+        wasi_unstable::RIGHT_FD_READ | wasi_unstable::RIGHT_FD_WRITE,
+        0,
+        0,
+        &mut fd_to,
+    );
+    assert_eq!(
+        status,
+        wasi_unstable::raw::__WASI_ESUCCESS,
+        "opening a file"
+    );
+    assert_gt!(
+        fd_to,
+        libc::STDERR_FILENO as wasi_unstable::Fd,
+        "file descriptor range check",
+    );
+
+    // Renumber fd of file1 into fd of file2
+    assert!(
+        wasi_unstable::fd_renumber(fd_from, fd_to).is_ok(),
+        "renumbering two descriptors",
+    );
+
+    // Ensure that fd_from is closed
+    assert_eq!(
+        wasi_unstable::fd_close(fd_from),
+        Err(wasi_unstable::EBADF),
+        "closing already closed file descriptor"
+    );
+
+    // Ensure that fd_to is still open.
+    let mut fdstat_to: wasi_unstable::FdStat = mem::zeroed();
+    status = wasi_fd_fdstat_get(fd_to, &mut fdstat_to);
+    assert_eq!(
+        status,
+        wasi_unstable::raw::__WASI_ESUCCESS,
+        "calling fd_fdstat on the open file descriptor"
+    );
+    assert_eq!(
+        fdstat_from.fs_filetype, fdstat_to.fs_filetype,
+        "expected fd_to have the same fdstat as fd_from"
+    );
+    assert_eq!(
+        fdstat_from.fs_flags, fdstat_to.fs_flags,
+        "expected fd_to have the same fdstat as fd_from"
+    );
+    assert_eq!(
+        fdstat_from.fs_rights_base, fdstat_to.fs_rights_base,
+        "expected fd_to have the same fdstat as fd_from"
+    );
+    assert_eq!(
+        fdstat_from.fs_rights_inheriting, fdstat_to.fs_rights_inheriting,
+        "expected fd_to have the same fdstat as fd_from"
+    );
+
+    close_fd(fd_to);
+}
+
+fn main() {
+    let mut args = env::args();
+    let prog = args.next().unwrap();
+    let arg = if let Some(arg) = args.next() {
+        arg
+    } else {
+        eprintln!("usage: {} <scratch directory>", prog);
+        process::exit(1);
+    };
+
+    // Open scratch directory
+    let dir_fd = match open_scratch_directory(&arg) {
+        Ok(dir_fd) => dir_fd,
+        Err(err) => {
+            eprintln!("{}", err);
+            process::exit(1)
+        }
+    };
+
+    // Run the tests.
+    unsafe { test_renumber(dir_fd) }
+}

crates/test-programs/wasi-tests/src/bin/sched_yield.rs

@@ -0,0 +1,10 @@
+use wasi::wasi_unstable;
+
+fn test_sched_yield() {
+    assert!(wasi_unstable::sched_yield().is_ok(), "sched_yield");
+}
+
+fn main() {
+    // Run tests
+    test_sched_yield()
+}

crates/test-programs/wasi-tests/src/bin/symlink_loop.rs

@@ -0,0 +1,47 @@
+use std::{env, process};
+use wasi::wasi_unstable;
+use wasi_tests::open_scratch_directory;
+use wasi_tests::utils::cleanup_file;
+use wasi_tests::wasi_wrappers::{wasi_path_open, wasi_path_symlink};
+
+unsafe fn test_symlink_loop(dir_fd: wasi_unstable::Fd) {
+    // Create a self-referencing symlink.
+    assert!(
+        wasi_path_symlink("symlink", dir_fd, "symlink").is_ok(),
+        "creating a symlink"
+    );
+
+    // Try to open it.
+    let mut file_fd: wasi_unstable::Fd = wasi_unstable::Fd::max_value() - 1;
+    assert_eq!(
+        wasi_path_open(dir_fd, 0, "symlink", 0, 0, 0, 0, &mut file_fd),
+        wasi_unstable::raw::__WASI_ELOOP,
+        "opening a self-referencing symlink",
+    );
+
+    // Clean up.
+    cleanup_file(dir_fd, "symlink");
+}
+
+fn main() {
+    let mut args = env::args();
+    let prog = args.next().unwrap();
+    let arg = if let Some(arg) = args.next() {
+        arg
+    } else {
+        eprintln!("usage: {} <scratch directory>", prog);
+        process::exit(1);
+    };
+
+    // Open scratch directory
+    let dir_fd = match open_scratch_directory(&arg) {
+        Ok(dir_fd) => dir_fd,
+        Err(err) => {
+            eprintln!("{}", err);
+            process::exit(1)
+        }
+    };
+
+    // Run the tests.
+    unsafe { test_symlink_loop(dir_fd) }
+}

crates/test-programs/wasi-tests/src/bin/truncation_rights.rs

@@ -0,0 +1,157 @@
+use std::{env, mem, process};
+use wasi::wasi_unstable;
+use wasi_tests::open_scratch_directory;
+use wasi_tests::utils::{cleanup_file, close_fd, create_file};
+use wasi_tests::wasi_wrappers::{wasi_fd_fdstat_get, wasi_path_open};
+
+unsafe fn test_truncation_rights(dir_fd: wasi_unstable::Fd) {
+    // Create a file in the scratch directory.
+    create_file(dir_fd, "file");
+
+    // Get the rights for the scratch directory.
+    let mut dir_fdstat: wasi_unstable::FdStat = mem::zeroed();
+    let mut status = wasi_fd_fdstat_get(dir_fd, &mut dir_fdstat);
+    assert_eq!(
+        status,
+        wasi_unstable::raw::__WASI_ESUCCESS,
+        "calling fd_fdstat on the scratch directory"
+    );
+    assert_eq!(
+        dir_fdstat.fs_filetype,
+        wasi_unstable::FILETYPE_DIRECTORY,
+        "expected the scratch directory to be a directory",
+    );
+    assert_eq!(
+        dir_fdstat.fs_flags, 0,
+        "expected the scratch directory to have no special flags",
+    );
+    assert_eq!(
+        dir_fdstat.fs_rights_base & wasi_unstable::RIGHT_FD_FILESTAT_SET_SIZE,
+        0,
+        "directories shouldn't have the fd_filestat_set_size right",
+    );
+
+    // If we have the right to set sizes from paths, test that it works.
+    if (dir_fdstat.fs_rights_base & wasi_unstable::RIGHT_PATH_FILESTAT_SET_SIZE) == 0 {
+        eprintln!("implementation doesn't support setting file sizes, skipping");
+    } else {
+        // Test that we can truncate the file.
+        let mut file_fd: wasi_unstable::Fd = wasi_unstable::Fd::max_value() - 1;
+        status = wasi_path_open(
+            dir_fd,
+            0,
+            "file",
+            wasi_unstable::O_TRUNC,
+            0,
+            0,
+            0,
+            &mut file_fd,
+        );
+        assert_eq!(
+            status,
+            wasi_unstable::raw::__WASI_ESUCCESS,
+            "truncating a file"
+        );
+        close_fd(file_fd);
+
+        let mut rights_base: wasi_unstable::Rights = dir_fdstat.fs_rights_base;
+        let mut rights_inheriting: wasi_unstable::Rights = dir_fdstat.fs_rights_inheriting;
+
+        if (rights_inheriting & wasi_unstable::RIGHT_FD_FILESTAT_SET_SIZE) == 0 {
+            eprintln!("implementation doesn't support setting file sizes through file descriptors, skipping");
+        } else {
+            rights_inheriting &= !wasi_unstable::RIGHT_FD_FILESTAT_SET_SIZE;
+            assert!(
+                wasi_unstable::fd_fdstat_set_rights(dir_fd, rights_base, rights_inheriting).is_ok(),
+                "droping fd_filestat_set_size inheriting right on a directory",
+            );
+        }
+
+        // Test that we can truncate the file without the
+        // wasi_unstable::RIGHT_FD_FILESTAT_SET_SIZE right.
+        status = wasi_path_open(
+            dir_fd,
+            0,
+            "file",
+            wasi_unstable::O_TRUNC,
+            0,
+            0,
+            0,
+            &mut file_fd,
+        );
+        assert_eq!(
+            status,
+            wasi_unstable::raw::__WASI_ESUCCESS,
+            "truncating a file without fd_filestat_set_size right",
+        );
+        close_fd(file_fd);
+
+        rights_base &= !wasi_unstable::RIGHT_PATH_FILESTAT_SET_SIZE;
+        assert!(
+            wasi_unstable::fd_fdstat_set_rights(dir_fd, rights_base, rights_inheriting).is_ok(),
+            "droping path_filestat_set_size base right on a directory",
+        );
+
+        // Test that clearing wasi_unstable::RIGHT_PATH_FILESTAT_SET_SIZE actually
+        // took effect.
+        status = wasi_fd_fdstat_get(dir_fd, &mut dir_fdstat);
+        assert_eq!(
+            status,
+            wasi_unstable::raw::__WASI_ESUCCESS,
+            "reading the fdstat from a directory",
+        );
+        assert_eq!(
+            (dir_fdstat.fs_rights_base & wasi_unstable::RIGHT_PATH_FILESTAT_SET_SIZE),
+            0,
+            "reading the fdstat from a directory",
+        );
+
+        // Test that we can't truncate the file without the
+        // wasi_unstable::RIGHT_PATH_FILESTAT_SET_SIZE right.
+        status = wasi_path_open(
+            dir_fd,
+            0,
+            "file",
+            wasi_unstable::O_TRUNC,
+            0,
+            0,
+            0,
+            &mut file_fd,
+        );
+        assert_eq!(
+            status,
+            wasi_unstable::raw::__WASI_ENOTCAPABLE,
+            "truncating a file without path_filestat_set_size right",
+        );
+        assert_eq!(
+            file_fd,
+            wasi_unstable::Fd::max_value(),
+            "failed open should set the file descriptor to -1",
+        );
+    }
+
+    cleanup_file(dir_fd, "file");
+}
+
+fn main() {
+    let mut args = env::args();
+    let prog = args.next().unwrap();
+    let arg = if let Some(arg) = args.next() {
+        arg
+    } else {
+        eprintln!("usage: {} <scratch directory>", prog);
+        process::exit(1);
+    };
+
+    // Open scratch directory
+    let dir_fd = match open_scratch_directory(&arg) {
+        Ok(dir_fd) => dir_fd,
+        Err(err) => {
+            eprintln!("{}", err);
+            process::exit(1)
+        }
+    };
+
+    // Run the tests.
+    unsafe { test_truncation_rights(dir_fd) }
+}

crates/test-programs/wasi-tests/src/bin/unlink_file_trailing_slashes.rs

@@ -0,0 +1,67 @@
+use std::{env, process};
+use wasi::wasi_unstable;
+use wasi_tests::open_scratch_directory;
+use wasi_tests::utils::{cleanup_dir, create_dir, create_file};
+use wasi_tests::wasi_wrappers::wasi_path_unlink_file;
+
+unsafe fn test_unlink_file_trailing_slashes(dir_fd: wasi_unstable::Fd) {
+    // Create a directory in the scratch directory.
+    create_dir(dir_fd, "dir");
+
+    // Test that unlinking it fails.
+    assert_eq!(
+        wasi_path_unlink_file(dir_fd, "dir"),
+        Err(wasi_unstable::EISDIR),
+        "unlink_file on a directory should fail"
+    );
+
+    // Test that unlinking it with a trailing flash fails.
+    assert_eq!(
+        wasi_path_unlink_file(dir_fd, "dir/"),
+        Err(wasi_unstable::EISDIR),
+        "unlink_file on a directory should fail"
+    );
+
+    // Clean up.
+    cleanup_dir(dir_fd, "dir");
+
+    // Create a temporary file.
+    create_file(dir_fd, "file");
+
+    // Test that unlinking it with a trailing flash fails.
+    assert_eq!(
+        wasi_path_unlink_file(dir_fd, "file/"),
+        Err(wasi_unstable::ENOTDIR),
+        "unlink_file with a trailing slash should fail"
+    );
+
+    // Test that unlinking it with no trailing flash succeeds.
+    assert_eq!(
+        wasi_path_unlink_file(dir_fd, "file"),
+        Ok(()),
+        "unlink_file with no trailing slash should succeed"
+    );
+}
+
+fn main() {
+    let mut args = env::args();
+    let prog = args.next().unwrap();
+    let arg = if let Some(arg) = args.next() {
+        arg
+    } else {
+        eprintln!("usage: {} <scratch directory>", prog);
+        process::exit(1);
+    };
+
+    // Open scratch directory
+    let dir_fd = match open_scratch_directory(&arg) {
+        Ok(dir_fd) => dir_fd,
+        Err(err) => {
+            eprintln!("{}", err);
+            process::exit(1)
+        }
+    };
+
+    // Run the tests.
+    unsafe { test_unlink_file_trailing_slashes(dir_fd) }
+}

crates/test-programs/wasi-tests/src/lib.rs

@@ -0,0 +1,25 @@
+pub mod utils;
+pub mod wasi_wrappers;
+
+use libc;
+use std::ffi::CString;
+use std::io;
+use wasi::wasi_unstable;
+
+pub fn open_scratch_directory(path: &str) -> Result<wasi_unstable::Fd, String> {
+    // Open the scratch directory.
+    let dir_fd: wasi_unstable::Fd = unsafe {
+        let cstr = CString::new(path.as_bytes()).unwrap();
+        libc::open(cstr.as_ptr(), libc::O_RDONLY | libc::O_DIRECTORY)
+    } as wasi_unstable::Fd;
+
+    if (dir_fd as std::os::raw::c_int) < 0 {
+        Err(format!(
+            "error opening scratch directory '{}': {}",
+            path,
+            io::Error::last_os_error()
+        ))
+    } else {
+        Ok(dir_fd)
+    }
+}

crates/test-programs/wasi-tests/src/utils.rs

@@ -0,0 +1,54 @@
+use crate::wasi_wrappers::*;
+use more_asserts::assert_gt;
+use wasi::wasi_unstable;
+
+pub unsafe fn create_dir(dir_fd: wasi_unstable::Fd, dir_name: &str) {
+    assert!(
+        wasi_path_create_directory(dir_fd, dir_name).is_ok(),
+        "creating a directory"
+    );
+}
+
+pub unsafe fn cleanup_dir(dir_fd: wasi_unstable::Fd, dir_name: &str) {
+    assert!(
+        wasi_path_remove_directory(dir_fd, dir_name).is_ok(),
+        "remove_directory on an empty directory should succeed"
+    );
+}
+
+/// Create an empty file with the given name.
+pub unsafe fn create_file(dir_fd: wasi_unstable::Fd, file_name: &str) {
+    let mut file_fd = wasi_unstable::Fd::max_value() - 1;
+    let status = wasi_path_open(
+        dir_fd,
+        0,
+        file_name,
+        wasi_unstable::O_CREAT,
+        0,
+        0,
+        0,
+        &mut file_fd,
+    );
+    assert_eq!(
+        status,
+        wasi_unstable::raw::__WASI_ESUCCESS,
+        "creating a file"
+    );
+    assert_gt!(
+        file_fd,
+        libc::STDERR_FILENO as wasi_unstable::Fd,
+        "file descriptor range check",
+    );
+    close_fd(file_fd);
+}
+
+pub unsafe fn cleanup_file(dir_fd: wasi_unstable::Fd, file_name: &str) {
+    assert!(
+        wasi_path_unlink_file(dir_fd, file_name).is_ok(),
+        "unlink_file on a symlink should succeed"
+    );
+}
+
+pub unsafe fn close_fd(fd: wasi_unstable::Fd) {
+    assert!(wasi_unstable::fd_close(fd).is_ok(), "closing a file");
+}

crates/test-programs/wasi-tests/src/wasi_wrappers.rs

@@ -0,0 +1,233 @@
+//! Minimal wrappers around WASI functions to allow use of `&str` rather than
+//! pointer-length pairs.
+//!
+//! Where possible, we use the idiomatic wasi_unstable wrappers rather than the
+//! raw interfaces, however for functions with out parameters, we use the raw
+//! interfaces so that we can test whether they are stored to. In the future,
+//! WASI should switch to multi-value and eliminate out parameters altogether.
+
+use wasi::wasi_unstable;
+
+pub unsafe fn wasi_path_create_directory(
+    dir_fd: wasi_unstable::Fd,
+    dir_name: &str,
+) -> Result<(), wasi_unstable::Error> {
+    wasi_unstable::path_create_directory(dir_fd, dir_name.as_bytes())
+}
+
+pub unsafe fn wasi_path_remove_directory(
+    dir_fd: wasi_unstable::Fd,
+    dir_name: &str,
+) -> Result<(), wasi_unstable::Error> {
+    wasi_unstable::path_remove_directory(dir_fd, dir_name.as_bytes())
+}
+
+pub unsafe fn wasi_path_unlink_file(
+    dir_fd: wasi_unstable::Fd,
+    file_name: &str,
+) -> Result<(), wasi_unstable::Error> {
+    wasi_unstable::path_unlink_file(dir_fd, file_name.as_bytes())
+}
+
+#[allow(clippy::too_many_arguments)]
+pub unsafe fn wasi_path_open(
+    dirfd: wasi_unstable::Fd,
+    dirflags: wasi_unstable::LookupFlags,
+    path: &str,
+    oflags: wasi_unstable::OFlags,
+    fs_rights_base: wasi_unstable::Rights,
+    fs_rights_inheriting: wasi_unstable::Rights,
+    fs_flags: wasi_unstable::FdFlags,
+    fd: &mut wasi_unstable::Fd,
+) -> wasi_unstable::Errno {
+    wasi_unstable::raw::__wasi_path_open(
+        dirfd,
+        dirflags,
+        path.as_ptr(),
+        path.len(),
+        oflags,
+        fs_rights_base,
+        fs_rights_inheriting,
+        fs_flags,
+        fd,
+    )
+}
+
+pub unsafe fn wasi_path_symlink(
+    old_path: &str,
+    dirfd: wasi_unstable::Fd,
+    new_path: &str,
+) -> Result<(), wasi_unstable::Error> {
+    wasi_unstable::path_symlink(old_path.as_bytes(), dirfd, new_path.as_bytes())
+}
+
+pub unsafe fn wasi_path_link(
+    old_fd: wasi_unstable::Fd,
+    old_flags: wasi_unstable::LookupFlags,
+    old_path: &str,
+    new_fd: wasi_unstable::Fd,
+    new_path: &str,
+) -> Result<(), wasi_unstable::Error> {
+    wasi_unstable::path_link(
+        old_fd,
+        old_flags,
+        old_path.as_bytes(),
+        new_fd,
+        new_path.as_bytes(),
+    )
+}
+
+pub unsafe fn wasi_path_readlink(
+    dirfd: wasi_unstable::Fd,
+    path: &str,
+    buf: &mut [u8],
+    bufused: &mut usize,
+) -> wasi_unstable::Errno {
+    wasi_unstable::raw::__wasi_path_readlink(
+        dirfd,
+        path.as_ptr(),
+        path.len(),
+        buf.as_mut_ptr(),
+        buf.len(),
+        bufused,
+    )
+}
+
+pub unsafe fn wasi_path_rename(
+    old_dirfd: wasi_unstable::Fd,
+    old_path: &str,
+    new_dirfd: wasi_unstable::Fd,
+    new_path: &str,
+) -> Result<(), wasi_unstable::Error> {
+    wasi_unstable::path_rename(
+        old_dirfd,
+        old_path.as_bytes(),
+        new_dirfd,
+        new_path.as_bytes(),
+    )
+}
+
+pub unsafe fn wasi_fd_fdstat_get(
+    fd: wasi_unstable::Fd,
+    fdstat: &mut wasi_unstable::FdStat,
+) -> wasi_unstable::Errno {
+    wasi_unstable::raw::__wasi_fd_fdstat_get(fd, fdstat)
+}
+
+pub unsafe fn wasi_fd_seek(
+    fd: wasi_unstable::Fd,
+    offset: wasi_unstable::FileDelta,
+    whence: wasi_unstable::Whence,
+    newoffset: &mut wasi_unstable::FileSize,
+) -> wasi_unstable::Errno {
+    wasi_unstable::raw::__wasi_fd_seek(fd, offset, whence, newoffset)
+}
+
+pub unsafe fn wasi_fd_tell(
+    fd: wasi_unstable::Fd,
+    offset: &mut wasi_unstable::FileSize,
+) -> wasi_unstable::Errno {
+    wasi_unstable::raw::__wasi_fd_tell(fd, offset)
+}
+
+pub unsafe fn wasi_clock_time_get(
+    clock_id: wasi_unstable::ClockId,
+    precision: wasi_unstable::Timestamp,
+    time: &mut wasi_unstable::Timestamp,
+) -> wasi_unstable::Errno {
+    wasi_unstable::raw::__wasi_clock_time_get(clock_id, precision, time)
+}
+
+pub unsafe fn wasi_fd_filestat_get(
+    fd: wasi_unstable::Fd,
+    filestat: &mut wasi_unstable::FileStat,
+) -> wasi_unstable::Errno {
+    wasi_unstable::raw::__wasi_fd_filestat_get(fd, filestat)
+}
+
+pub unsafe fn wasi_fd_write(
+    fd: wasi_unstable::Fd,
+    iovs: &[wasi_unstable::CIoVec],
+    nwritten: &mut libc::size_t,
+) -> wasi_unstable::Errno {
+    wasi_unstable::raw::__wasi_fd_write(fd, iovs.as_ptr(), iovs.len(), nwritten)
+}
+
+pub unsafe fn wasi_fd_read(
+    fd: wasi_unstable::Fd,
+    iovs: &[wasi_unstable::IoVec],
+    nread: &mut libc::size_t,
+) -> wasi_unstable::Errno {
+    wasi_unstable::raw::__wasi_fd_read(fd, iovs.as_ptr(), iovs.len(), nread)
+}
+
+pub unsafe fn wasi_fd_pread(
+    fd: wasi_unstable::Fd,
+    iovs: &[wasi_unstable::IoVec],
+    offset: wasi_unstable::FileSize,
+    nread: &mut usize,
+) -> wasi_unstable::Errno {
+    wasi_unstable::raw::__wasi_fd_pread(fd, iovs.as_ptr(), iovs.len(), offset, nread)
+}
+
+pub unsafe fn wasi_fd_pwrite(
+    fd: wasi_unstable::Fd,
+    iovs: &mut [wasi_unstable::CIoVec],
+    offset: wasi_unstable::FileSize,
+    nwritten: &mut usize,
+) -> wasi_unstable::Errno {
+    wasi_unstable::raw::__wasi_fd_pwrite(fd, iovs.as_ptr(), iovs.len(), offset, nwritten)
+}
+
+pub unsafe fn wasi_path_filestat_get(
+    fd: wasi_unstable::Fd,
+    dirflags: wasi_unstable::LookupFlags,
+    path: &str,
+    path_len: usize,
+    filestat: &mut wasi_unstable::FileStat,
+) -> wasi_unstable::Errno {
+    wasi_unstable::raw::__wasi_path_filestat_get(fd, dirflags, path.as_ptr(), path_len, filestat)
+}
+
+pub unsafe fn wasi_path_filestat_set_times(
+    fd: wasi_unstable::Fd,
+    dirflags: wasi_unstable::LookupFlags,
+    path: &str,
+    st_atim: wasi_unstable::Timestamp,
+    st_mtim: wasi_unstable::Timestamp,
+    fst_flags: wasi_unstable::FstFlags,
+) -> Result<(), wasi_unstable::Error> {
+    wasi_unstable::path_filestat_set_times(
+        fd,
+        dirflags,
+        path.as_bytes(),
+        st_atim,
+        st_mtim,
+        fst_flags,
+    )
+}
+
+pub unsafe fn wasi_fd_readdir(
+    fd: wasi_unstable::Fd,
+    buf: &mut [u8],
+    buf_len: usize,
+    cookie: wasi_unstable::DirCookie,
+    buf_used: &mut usize,
+) -> wasi_unstable::Errno {
+    wasi_unstable::raw::__wasi_fd_readdir(
+        fd,
+        buf.as_mut_ptr() as *mut libc::c_void,
+        buf_len,
+        cookie,
+        buf_used,
+    )
+}
+
+pub unsafe fn wasi_fd_advise(
+    fd: wasi_unstable::Fd,
+    offset: wasi_unstable::FileSize,
+    len: wasi_unstable::FileSize,
+    advice: wasi_unstable::Advice,
+) -> wasi_unstable::Errno {
+    wasi_unstable::raw::__wasi_fd_advise(fd, offset, len, advice)
+}