Implement FS.rmdir with WasmFS (#18952)

Author: kshitjj

emcc.py

@@ -2325,6 +2325,7 @@ def phase_linker_setup(options, state, newargs):
         '_wasmfs_mkdir',
         '_wasmfs_unlink',
         '_wasmfs_chdir',
+        '_wasmfs_rmdir',
         '_wasmfs_symlink',
         '_wasmfs_chmod',
         '_wasmfs_identify',

emscripten.py

@@ -885,6 +885,8 @@ def create_wasm64_wrappers(metadata):
     '_emscripten_thread_free_data': '_p',
     '_emscripten_dlsync_self_async': '_p',
     '_emscripten_proxy_dlsync_async': '_pp',
+    '_wasmfs_rmdir': '_p',
+    '_wasmfs_unlink': '_p'
   }
 
   wasm64_wrappers = '''

src/library_wasmfs.js

@@ -140,6 +140,12 @@ mergeInto(LibraryManager.library, {
     },
     // TODO: mkdirTree
     // TDOO: rmdir
+    rmdir: (path) => {
+      return withStackSave(() => {
+        var buffer = stringToUTF8OnStack(path);
+        return __wasmfs_rmdir(buffer);
+      })
+    },
     // TODO: open
     open: (path, flags, mode) => {
       flags = typeof flags == 'string' ? FS.modeStringToFlags(flags) : flags;

system/lib/wasmfs/js_api.cpp

@@ -100,6 +100,8 @@ int _wasmfs_mkdir(char* path, int mode) {
   return __syscall_mkdirat(AT_FDCWD, (intptr_t)path, mode);
 }
 
+int _wasmfs_rmdir(char* path){ return __syscall_unlinkat(AT_FDCWD, (intptr_t)path, AT_REMOVEDIR); }
+
 int _wasmfs_open(char* path, int flags, mode_t mode) {
   return __syscall_openat(AT_FDCWD, (intptr_t)path, flags, mode);
 }

test/fs/test_dir.c

@@ -0,0 +1,49 @@
+/*
+ * Copyright 2023 The Emscripten Authors.  All rights reserved.
+ * Emscripten is available under two separate licenses, the MIT license and the
+ * University of Illinois/NCSA Open Source License.  Both these licenses can be
+ * found in the LICENSE file.
+ */
+
+#include <assert.h>
+#include <emscripten/emscripten.h>
+#include <stdio.h>
+
+int main() {
+  EM_ASM(
+    // Create multiple directories
+    var err = FS.mkdir('/dir1');
+    assert(!err);
+    err = FS.mkdir('/dir2');
+    assert(!err);
+
+    // Remove the multiple directories
+    err = FS.rmdir('/dir1');
+    assert(!err);
+    err = FS.rmdir('/dir2');
+    assert(!err);
+        
+    // Create a directory with a file inside it
+    var err = FS.mkdir('/test_dir');
+    assert(!err);
+    err = FS.writeFile('/test_dir/file.txt', 'Hello World!');
+    assert(!err);
+
+    // Attempt to remove the directory (should fail)
+    err = FS.rmdir('/test_dir');
+    assert(err);
+
+    // Remove the file and then the directory
+    err = FS.unlink('/test_dir/file.txt');
+    assert(!err);
+    err = FS.rmdir('/test_dir');
+    assert(!err);
+
+    // Attempt to remove a non-existent directory (should fail)
+    var err = FS.rmdir('/non_existent_dir');
+    assert(err);
+  );
+  puts("success");
+
+  return 0;
+}

test/test_core.py

@@ -5953,6 +5953,11 @@ def test_istream(self):
       self.set_setting('LINKABLE', linkable)
       self.do_core_test('test_istream.cpp')
 
+  def test_fs_dir_wasmfs(self):
+    self.emcc_args += ['-sWASMFS']
+    self.emcc_args += ['-sFORCE_FILESYSTEM']
+    self.do_runf(test_file('fs/test_dir.c'), 'success')
+
   def test_fs_base(self):
     self.set_setting('DEFAULT_LIBRARY_FUNCS_TO_INCLUDE', ['$FS'])
     self.uses_es6 = True