add fd_sync test

lib/wasi-tests/tests/wasitests/fd_sync.rs

@@ -0,0 +1,14 @@
+#[test]
+fn test_fd_sync() {
+    assert_wasi_output!(
+        "../../wasitests/fd_sync.wasm",
+        "fd_sync",
+        vec![],
+        vec![(
+            ".".to_string(),
+            ::std::path::PathBuf::from("wasitests/test_fs/temp")
+        ),],
+        vec![],
+        "../../wasitests/fd_sync.out"
+    );
+}

lib/wasi-tests/tests/wasitests/mod.rs

@@ -9,6 +9,7 @@ mod create_dir;
 mod envvar;
 mod fd_allocate;
 mod fd_pread;
+mod fd_sync;
 mod file_metadata;
 mod fs_sandbox_test;
 mod fseek;

lib/wasi-tests/wasitests/fd_allocate.rs

@@ -6,13 +6,6 @@ use std::fs;
 use std::os::wasi::prelude::AsRawFd;
 use std::path::PathBuf;
 
-#[cfg(target_os = "wasi")]
-#[repr(C)]
-struct WasiIovec {
-    pub buf: u32,
-    pub buf_len: u32,
-}
-
 #[cfg(target_os = "wasi")]
 #[link(wasm_import_module = "wasi_unstable")]
 extern "C" {

lib/wasi-tests/wasitests/fd_sync.out

@@ -0,0 +1,2 @@
+170
+1404

lib/wasi-tests/wasitests/fd_sync.rs

@@ -0,0 +1,56 @@
+// Args:
+// mapdir: .:wasitests/test_fs/temp
+
+use std::fs;
+use std::path::PathBuf;
+
+#[cfg(target_os = "wasi")]
+#[link(wasm_import_module = "wasi_unstable")]
+extern "C" {
+    fn fd_sync(fd: u32) -> u16;
+}
+
+#[cfg(target_os = "wasi")]
+fn sync(fd: u32) -> u16 {
+    unsafe { fd_sync(fd) }
+}
+
+fn main() {
+    #[cfg(target_os = "wasi")]
+    let mut base = PathBuf::from(".");
+    #[cfg(target_os = "wasi")]
+    {
+        base.push("fd_sync_file.txt");
+        let mut file = fs::OpenOptions::new()
+            .create(true)
+            .write(true)
+            .truncate(true)
+            .open(&base)
+            .expect("Could not create file");
+        let mut buffer = [0u8; 64];
+
+        {
+            use std::io::Write;
+            // example text from https://www.un.org/en/universal-declaration-human-rights/
+            file.write_all(b"All human beings are born free and equal in dignity and rights. They are endowed with reason and conscience and should act towards one another in a spirit of brotherhood.").unwrap();
+            file.sync_all();
+            let len = file.metadata().unwrap().len();
+            println!("{}", len);
+            assert_eq!(len, 170);
+            file.set_len(170 + 1234);
+            file.sync_all();
+            let len = file.metadata().unwrap().len();
+            println!("{}", len);
+            assert_eq!(len, 1234 + 170);
+        }
+    }
+    #[cfg(target_os = "wasi")]
+    std::fs::remove_file(&base).unwrap();
+
+    #[cfg(not(target_os = "wasi"))]
+    {
+        // eh, just print the output directly
+        println!("170");
+        println!("1404");
+    }
+}

lib/wasi/src/syscalls/mod.rs

@@ -1146,6 +1146,7 @@ pub fn fd_seek(
 /// - `__WASI_ENOTCAPABLE`
 pub fn fd_sync(ctx: &mut Ctx, fd: __wasi_fd_t) -> __wasi_errno_t {
     debug!("wasi::fd_sync");
+    debug!("=> fd={}", fd);
     let memory = ctx.memory(0);
     let state = get_wasi_state(ctx);
     let fd_entry = wasi_try!(state.fs.get_fd(fd));