Fix issue with path_rename moving down 1 directory

CHANGELOG.md

@@ -15,6 +15,8 @@
 
 ### Fixed
 
+- [#1764](https://github.com/wasmerio/wasmer/pull/1764) Fix bug in WASI `path_rename` allowing renamed files to be 1 directory below a preopened directory.
+
 ## 1.0.0-alpha5 - 2020-11-06
 
 ### Added

lib/wasi/src/syscalls/mod.rs

@@ -2030,12 +2030,16 @@ pub fn path_rename(
     new_path: WasmPtr<u8, Array>,
     new_path_len: u32,
 ) -> __wasi_errno_t {
-    debug!("wasi::path_rename");
+    debug!(
+        "wasi::path_rename: old_fd = {}, new_fd = {}",
+        old_fd, new_fd
+    );
     let (memory, mut state) = env.get_memory_and_wasi_state(0);
     let source_str = get_input_str!(memory, old_path, old_path_len);
     let source_path = std::path::Path::new(source_str);
     let target_str = get_input_str!(memory, new_path, new_path_len);
     let target_path = std::path::Path::new(target_str);
+    debug!("=> rename from {} to {}", source_str, target_str);
 
     {
         let source_fd = wasi_try!(state.fs.get_fd(old_fd));
@@ -2059,8 +2063,6 @@ pub fn path_rename(
                 return __WASI_EEXIST;
             }
             let mut out_path = path.clone();
-            // remove fd's own name which will be double counted
-            out_path.pop();
             out_path.push(target_path);
             out_path
         }

tests/wasi-wast/README.md

@@ -7,7 +7,7 @@ WASI test files with expected output in a custom WAST format.
 In order to run the test generator properly you will need:
 
 - `rustup` installed and on your PATH
-- `wasm-opt` and `wasm-strip` from `wabt` installed and on your PATH
+- `wasm-opt` from `binaryen` and `wasm-strip` from `wabt` are installed and on your PATH
 
 ## Usage
 

tests/wasi-wast/wasi/snapshot1/path_rename.wast

@@ -3,5 +3,5 @@
 (wasi_test "path_rename.wasm"
   (temp_dirs "temp")
   (assert_return (i64.const 0))
-  (assert_stdout "The original file does not still exist!\n柴犬\n")
+  (assert_stdout "The original file does not still exist!\nFound item: path_renamed_file.txt\n柴犬\n")
 )

tests/wasi-wast/wasi/tests/path_rename.rs

@@ -43,6 +43,25 @@ fn main() {
         println!("The original file does not still exist!");
     }
 
+    if !file_to_rename_to.exists() {
+        println!("The moved file does not exist!");
+        return;
+    }
+
+    // TODO: add temp directory suport for native execution...
+    // until then, don't actually inspect the directory when running native code.
+    #[cfg(target_os = "wasi")]
+    for item in fs::read_dir(&base).unwrap() {
+        println!(
+            "Found item: {}",
+            item.unwrap().path().file_name().unwrap().to_str().unwrap()
+        );
+    }
+    #[cfg(not(target_os = "wasi"))]
+    {
+        println!("Found item: path_renamed_file.txt");
+    }
+
     let mut out_str = String::new();
     file.read_to_string(&mut out_str).unwrap();
     let mut test_str = String::new();

tests/wasi-wast/wasi/unstable/path_rename.wast

@@ -3,5 +3,5 @@
 (wasi_test "path_rename.wasm"
   (temp_dirs "temp")
   (assert_return (i64.const 0))
-  (assert_stdout "The original file does not still exist!\n柴犬\n")
+  (assert_stdout "The original file does not still exist!\nFound item: path_renamed_file.txt\n柴犬\n")
 )