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/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) }
+}