From 53b592067630fda20304492ced5b5b64e934a69b Mon Sep 17 00:00:00 2001
From: Kleis Auke Wolthuizen <github@kleisauke.nl>
Date: Thu, 17 Jul 2025 21:21:52 +0200
Subject: [PATCH 1/7] [WasmFS] Fix absolute path access under NODERAWFS

Resolves: #24830.
Resolves: #24836.
---
 src/lib/libwasmfs_node.js                     |  6 ++--
 system/include/emscripten/wasmfs.h            |  7 +++-
 system/lib/wasmfs/backends/node_backend.cpp   |  8 +++--
 system/lib/wasmfs/backends/noderawfs_root.cpp |  4 +++
 system/lib/wasmfs/wasmfs.cpp                  | 29 +++++++++++++--
 system/lib/wasmfs/wasmfs.h                    |  3 ++
 test/fs/test_fs_dev_random.c                  |  6 ++--
 test/test_core.py                             |  7 ++--
 test/test_other.py                            | 36 +++++++++++++++----
 9 files changed, 85 insertions(+), 21 deletions(-)

diff --git a/src/lib/libwasmfs_node.js b/src/lib/libwasmfs_node.js
index bf749467ffdc6..c0165c6bb4eef 100644
--- a/src/lib/libwasmfs_node.js
+++ b/src/lib/libwasmfs_node.js
@@ -31,7 +31,7 @@ addToLibrary({
     if (wasmfsNodeIsWindows) {
       // Node.js on Windows never represents permission bit 'x', so
       // propagate read bits to execute bits
-      stat.mode |= (stat.mode & {{{ cDefs.S_IRUSR | cDefs.S_IRGRP | cDefs.S_IROTH }}}) >> 2;
+      stat.mode |= (stat.mode & {{{ cDefs.S_IRUGO }}}) >> 2;
     }
     return stat;
   },
@@ -206,7 +206,7 @@ addToLibrary({
     return wasmfsTry(() => {
       // TODO: Cache open file descriptors to guarantee that opened files will
       // still exist when we try to access them.
-      let nread = fs.readSync(fd, new Int8Array(HEAPU8.buffer, buf_p, len), 0, len, pos);
+      let nread = fs.readSync(fd, HEAPU8, buf_p, len, pos);
       {{{ makeSetValue('nread_p', 0, 'nread', 'i32') }}};
       // implicitly return 0
     });
@@ -217,7 +217,7 @@ addToLibrary({
     return wasmfsTry(() => {
       // TODO: Cache open file descriptors to guarantee that opened files will
       // still exist when we try to access them.
-      let nwritten = fs.writeSync(fd, new Int8Array(HEAPU8.buffer, buf_p, len), 0, len, pos);
+      let nwritten = fs.writeSync(fd, HEAPU8, buf_p, len, pos);
       {{{ makeSetValue('nwritten_p', 0, 'nwritten', 'i32') }}};
       // implicitly return 0
     });
diff --git a/system/include/emscripten/wasmfs.h b/system/include/emscripten/wasmfs.h
index 024d0119ad09e..744458661f416 100644
--- a/system/include/emscripten/wasmfs.h
+++ b/system/include/emscripten/wasmfs.h
@@ -77,7 +77,7 @@ backend_t wasmfs_create_memory_backend(void);
 //
 backend_t wasmfs_create_fetch_backend(const char* _Nonnull base_url, uint32_t chunk_size);
 
-backend_t wasmfs_create_node_backend(const char* _Nonnull root);
+backend_t wasmfs_create_node_backend(const char* _Nonnull mount_path);
 
 // Note: this cannot be called on the browser main thread because it might
 // deadlock while waiting for the OPFS dedicated worker thread to be spawned.
@@ -111,6 +111,11 @@ void wasmfs_flush(void);
 // default backend is used.
 backend_t wasmfs_create_root_dir(void);
 
+// A hook users can do to create the working directory. Overriding this allows
+// the user to set a particular backend as the CWD. If this is not set then the
+// root_backend is used.
+backend_t wasmfs_create_working_dir(backend_t root_backend);
+
 // A hook users can do to run code during WasmFS startup. This hook happens
 // before file preloading, so user code could create backends and mount them,
 // which would then affect in which backend the preloaded files are loaded (the
diff --git a/system/lib/wasmfs/backends/node_backend.cpp b/system/lib/wasmfs/backends/node_backend.cpp
index a3a7ad19b32f3..5daabd5556055 100644
--- a/system/lib/wasmfs/backends/node_backend.cpp
+++ b/system/lib/wasmfs/backends/node_backend.cpp
@@ -191,7 +191,9 @@ class NodeDirectory : public Directory {
     if (_wasmfs_node_get_mode(childPath.c_str(), &mode)) {
       return nullptr;
     }
-    if (S_ISREG(mode)) {
+    // Allow reading from character device files (e.g. `/dev/random`,
+    // `/dev/urandom`)
+    if (S_ISREG(mode) || S_ISCHR(mode)) {
       return std::make_shared<NodeFile>(mode, getBackend(), childPath);
     } else if (S_ISDIR(mode)) {
       return std::make_shared<NodeDirectory>(mode, getBackend(), childPath);
@@ -300,8 +302,8 @@ class NodeBackend : public Backend {
 
 extern "C" {
 
-backend_t wasmfs_create_node_backend(const char* root) {
-  return wasmFS.addBackend(std::make_unique<NodeBackend>(root));
+backend_t wasmfs_create_node_backend(const char* mount_path) {
+  return wasmFS.addBackend(std::make_unique<NodeBackend>(mount_path));
 }
 
 void EMSCRIPTEN_KEEPALIVE _wasmfs_node_record_dirent(
diff --git a/system/lib/wasmfs/backends/noderawfs_root.cpp b/system/lib/wasmfs/backends/noderawfs_root.cpp
index 6ed7af81daf56..32788b60ba908 100644
--- a/system/lib/wasmfs/backends/noderawfs_root.cpp
+++ b/system/lib/wasmfs/backends/noderawfs_root.cpp
@@ -6,5 +6,9 @@
 #include "emscripten/wasmfs.h"
 
 backend_t wasmfs_create_root_dir(void) {
+  return wasmfs_create_node_backend("");
+}
+
+backend_t wasmfs_create_working_dir(backend_t root_backend) {
   return wasmfs_create_node_backend(".");
 }
diff --git a/system/lib/wasmfs/wasmfs.cpp b/system/lib/wasmfs/wasmfs.cpp
index 7a771a8ff4bd0..b4fb7b0d563d4 100644
--- a/system/lib/wasmfs/wasmfs.cpp
+++ b/system/lib/wasmfs/wasmfs.cpp
@@ -37,7 +37,8 @@ __attribute__((init_priority(100))) WasmFS wasmFS;
 __attribute__((weak)) extern "C" void wasmfs_before_preload(void) {}
 
 // Set up global data structures and preload files.
-WasmFS::WasmFS() : rootDirectory(initRootDirectory()), cwd(rootDirectory) {
+WasmFS::WasmFS()
+  : rootDirectory(initRootDirectory()), cwd(initCWD(rootDirectory)) {
   wasmfs_before_preload();
   preloadFiles();
 }
@@ -87,8 +88,8 @@ WasmFS::~WasmFS() {
   rootDirectory->locked().setParent(nullptr);
 }
 
-// Special backends that want to install themselves as the root use this hook.
-// Otherwise, we use the default backends.
+// Hooks for backends that want to install themselves as the root or CWD.
+// Otherwise, we use the default memory backends.
 __attribute__((weak)) extern "C" backend_t wasmfs_create_root_dir(void) {
 #ifdef WASMFS_CASE_INSENSITIVE
   return createIgnoreCaseBackend([]() { return createMemoryBackend(); });
@@ -97,6 +98,11 @@ __attribute__((weak)) extern "C" backend_t wasmfs_create_root_dir(void) {
 #endif
 }
 
+__attribute__((weak)) extern "C" backend_t
+wasmfs_create_working_dir(backend_t root_backend) {
+  return root_backend;
+}
+
 std::shared_ptr<Directory> WasmFS::initRootDirectory() {
   auto rootBackend = wasmfs_create_root_dir();
   auto rootDirectory =
@@ -126,6 +132,23 @@ std::shared_ptr<Directory> WasmFS::initRootDirectory() {
   return rootDirectory;
 }
 
+std::shared_ptr<Directory>
+WasmFS::initCWD(const std::shared_ptr<Directory>& root) {
+  auto rootBackend = root->getBackend();
+  auto cwdBackend = wasmfs_create_working_dir(rootBackend);
+  if (rootBackend == cwdBackend) {
+    return root;
+  }
+
+  auto cwd = cwdBackend->createDirectory(S_IRUGO | S_IXUGO | S_IWUGO);
+  auto lockedCwd = cwd->locked();
+
+  // The root directory is the parent of the CWD.
+  lockedCwd.setParent(root);
+
+  return cwd;
+}
+
 // Initialize files specified by the --preload-file option.
 // Set up directories and files in wasmFS$preloadedDirs and
 // wasmFS$preloadedFiles from JS. This function will be called before any file
diff --git a/system/lib/wasmfs/wasmfs.h b/system/lib/wasmfs/wasmfs.h
index 682d53064ee77..d369239a769c0 100644
--- a/system/lib/wasmfs/wasmfs.h
+++ b/system/lib/wasmfs/wasmfs.h
@@ -32,6 +32,9 @@ class WasmFS {
   // dev/stderr. Refers to the same std streams in the open file table.
   std::shared_ptr<Directory> initRootDirectory();
 
+  // Private method to initialize CWD once.
+  std::shared_ptr<Directory> initCWD(const std::shared_ptr<Directory>& root);
+
   // Initialize files specified by --preload-file option.
   void preloadFiles();
 
diff --git a/test/fs/test_fs_dev_random.c b/test/fs/test_fs_dev_random.c
index 4200f0bdc8139..a88a04fc75619 100644
--- a/test/fs/test_fs_dev_random.c
+++ b/test/fs/test_fs_dev_random.c
@@ -13,12 +13,14 @@ int main() {
   int nread;
 
   fp = fopen("/dev/random", "r");
-  nread = fread(&data, 1, byte_count, fp);
+  assert(fp != NULL);
+  nread = fread(data, 1, byte_count, fp);
   assert(nread == byte_count);
   fclose(fp);
 
   fp = fopen("/dev/urandom", "r");
-  nread = fread(&data, 1, byte_count, fp);
+  assert(fp != NULL);
+  nread = fread(data, 1, byte_count, fp);
   assert(nread == byte_count);
   fclose(fp);
 
diff --git a/test/test_core.py b/test/test_core.py
index dfdbdb1eba9ed..e190eb54ce570 100644
--- a/test/test_core.py
+++ b/test/test_core.py
@@ -6149,9 +6149,12 @@ def test_unistd_unlink(self):
 
     # Several differences/bugs on non-linux including https://github.com/nodejs/node/issues/18014
     # TODO: NODERAWFS in WasmFS
-    if '-DNODERAWFS' in self.cflags and os.geteuid() == 0:
+    if '-DNODERAWFS' in self.cflags:
       # 0 if root user
-      self.cflags += ['-DSKIP_ACCESS_TESTS']
+      if os.geteuid() == 0:
+        self.cflags += ['-DSKIP_ACCESS_TESTS']
+      if self.get_setting('WASMFS'):
+        self.skipTest('https://github.com/emscripten-core/emscripten/issues/18112')
 
     self.do_runf('unistd/unlink.c', 'success')
 
diff --git a/test/test_other.py b/test/test_other.py
index 936dff4783e1c..7c33c07af1f1b 100644
--- a/test/test_other.py
+++ b/test/test_other.py
@@ -9255,16 +9255,43 @@ def test_noderawfs_disables_embedding(self):
     self.assert_fail(base + ['--preload-file', 'somefile'], expected)
     self.assert_fail(base + ['--embed-file', 'somefile'], expected)
 
+  @crossplatform
+  @also_with_wasmfs
   def test_noderawfs_access_abspath(self):
     create_file('foo', 'bar')
     create_file('access.c', r'''
+      #include <stdio.h>
+      #include <assert.h>
       #include <unistd.h>
       int main(int argc, char** argv) {
-        return access(argv[1], F_OK);
+        printf("testing access to %s\n", argv[1]);
+        int rtn = access(argv[1], F_OK);
+        assert(rtn == 0);
+        return 0;
       }
     ''')
     self.do_runf('access.c', cflags=['-sNODERAWFS'], args=[os.path.abspath('foo')])
 
+  @crossplatform
+  @also_with_wasmfs
+  def test_noderawfs_open_abspath(self):
+    create_file('foo', 'bar')
+    create_file('open.c', r'''
+      #include <stdio.h>
+      #include <fcntl.h>
+      #include <assert.h>
+      #include <unistd.h>
+      int main(int argc, char** argv) {
+        printf("testing open to %s\n", argv[1]);
+        int fd = open(argv[1], O_RDONLY, 0644);
+        assert(fd >= 0);
+        int rtn = close(fd);
+        assert(rtn == 0);
+        return 0;
+      }
+    ''')
+    self.do_runf('open.c', cflags=['-sNODERAWFS'], args=[os.path.abspath('foo')])
+
   def test_noderawfs_readfile_prerun(self):
     create_file('foo', 'bar')
     self.add_pre_run("console.log(FS.readFile('foo', { encoding: 'utf8' }));")
@@ -13210,11 +13237,10 @@ def test_unistd_chown(self):
     self.set_setting('WASMFS')
     self.do_run_in_out_file_test('wasmfs/wasmfs_chown.c')
 
-  @wasmfs_all_backends
   def test_wasmfs_getdents(self):
     # Run only in WASMFS for now.
     self.set_setting('FORCE_FILESYSTEM')
-    self.do_run_in_out_file_test('wasmfs/wasmfs_getdents.c')
+    self.do_run_in_out_file_test('wasmfs/wasmfs_getdents.c', cflags=['-sWASMFS'])
 
   def test_wasmfs_jsfile(self):
     self.set_setting('WASMFS')
@@ -13801,15 +13827,11 @@ def test_fs_icase(self):
   @crossplatform
   @with_all_fs
   def test_std_filesystem(self):
-    if self.get_setting('NODERAWFS') and self.get_setting('WASMFS'):
-      self.skipTest('https://github.com/emscripten-core/emscripten/issues/24830')
     self.do_other_test('test_std_filesystem.cpp')
 
   @crossplatform
   @with_all_fs
   def test_std_filesystem_tempdir(self):
-    if self.get_setting('NODERAWFS') and self.get_setting('WASMFS'):
-      self.skipTest('https://github.com/emscripten-core/emscripten/issues/24830')
     self.do_other_test('test_std_filesystem_tempdir.cpp', cflags=['-g'])
 
   def test_strict_js_closure(self):

From 0a76c59cc82c5e18f1e3d2f596f11c7bee853ea0 Mon Sep 17 00:00:00 2001
From: Kleis Auke Wolthuizen <github@kleisauke.nl>
Date: Tue, 24 Mar 2026 10:17:10 +0100
Subject: [PATCH 2/7] [WiP] Try to fix Windows CI

---
 src/lib/libwasmfs_node.js                     | 23 ++++++++++++++-----
 system/lib/wasmfs/backend.h                   |  3 +++
 .../wasmfs/backends/ignore_case_backend.cpp   |  8 +++++++
 system/lib/wasmfs/backends/memory_backend.cpp |  6 +++++
 system/lib/wasmfs/backends/node_backend.cpp   | 13 +++++++++++
 system/lib/wasmfs/backends/node_backend.h     |  3 +++
 system/lib/wasmfs/backends/opfs_backend.cpp   |  8 +++++++
 system/lib/wasmfs/js_impl_backend.h           |  6 +++++
 system/lib/wasmfs/paths.cpp                   |  6 +++--
 .../wasmfs/proxied_async_js_impl_backend.h    |  8 +++++++
 10 files changed, 76 insertions(+), 8 deletions(-)

diff --git a/src/lib/libwasmfs_node.js b/src/lib/libwasmfs_node.js
index c0165c6bb4eef..ff94b68a77458 100644
--- a/src/lib/libwasmfs_node.js
+++ b/src/lib/libwasmfs_node.js
@@ -6,6 +6,7 @@
 
 addToLibrary({
   $wasmfsNodeIsWindows: !!process.platform.match(/^win/),
+  $nodePath: "require('node:path')",
 
   $wasmfsNodeConvertNodeCode__deps: ['$ERRNO_CODES'],
   $wasmfsNodeConvertNodeCode: (e) => {
@@ -157,15 +158,15 @@ addToLibrary({
   },
 
   _wasmfs_node_truncate__i53abi: true,
-  _wasmfs_node_truncate__deps : ['$wasmfsTry'],
-  _wasmfs_node_truncate : (path_p, len) => {
+  _wasmfs_node_truncate__deps: ['$wasmfsTry'],
+  _wasmfs_node_truncate: (path_p, len) => {
     if (isNaN(len)) return -{{{ cDefs.EOVERFLOW }}};
     return wasmfsTry(() => fs.truncateSync(UTF8ToString(path_p), len));
   },
 
   _wasmfs_node_ftruncate__i53abi: true,
-  _wasmfs_node_ftruncate__deps : ['$wasmfsTry'],
-  _wasmfs_node_ftruncate : (fd, len) => {
+  _wasmfs_node_ftruncate__deps: ['$wasmfsTry'],
+  _wasmfs_node_ftruncate: (fd, len) => {
     if (isNaN(len)) return -{{{ cDefs.EOVERFLOW }}};
     return wasmfsTry(() => fs.ftruncateSync(fd, len));
   },
@@ -212,8 +213,8 @@ addToLibrary({
     });
   },
 
-  _wasmfs_node_write__deps : ['$wasmfsTry'],
-  _wasmfs_node_write : (fd, buf_p, len, pos, nwritten_p) => {
+  _wasmfs_node_write__deps: ['$wasmfsTry'],
+  _wasmfs_node_write: (fd, buf_p, len, pos, nwritten_p) => {
     return wasmfsTry(() => {
       // TODO: Cache open file descriptors to guarantee that opened files will
       // still exist when we try to access them.
@@ -223,4 +224,14 @@ addToLibrary({
     });
   },
 
+  _wasmfs_node_path_is_abs__deps: ['$nodePath'],
+  _wasmfs_node_path_is_abs: (path_p) => {
+    return nodePath.isAbsolute(UTF8ToString(path_p));
+  },
+
+  _wasmfs_node_path_get_root__deps: ['$nodePath'],
+  _wasmfs_node_path_get_root: (abs_path_p, target_p, bufsize) => {
+    return stringToUTF8(nodePath.parse(UTF8ToString(abs_path_p)).root, target_p, bufsize);
+  },
+
 });
diff --git a/system/lib/wasmfs/backend.h b/system/lib/wasmfs/backend.h
index d8e584c01136a..31761a37764d5 100644
--- a/system/lib/wasmfs/backend.h
+++ b/system/lib/wasmfs/backend.h
@@ -21,6 +21,9 @@ class Backend {
   virtual std::shared_ptr<Directory> createDirectory(mode_t mode) = 0;
   virtual std::shared_ptr<Symlink> createSymlink(std::string target) = 0;
 
+  virtual bool isAbsolutePath(std::string_view path) = 0;
+  virtual std::string getRootPath(std::string_view abs_path) = 0;
+
   virtual ~Backend() = default;
 };
 
diff --git a/system/lib/wasmfs/backends/ignore_case_backend.cpp b/system/lib/wasmfs/backends/ignore_case_backend.cpp
index ba1f1f4e0b72a..46540ddf438e0 100644
--- a/system/lib/wasmfs/backends/ignore_case_backend.cpp
+++ b/system/lib/wasmfs/backends/ignore_case_backend.cpp
@@ -225,6 +225,14 @@ class IgnoreCaseBackend : public Backend {
   std::shared_ptr<Symlink> createSymlink(std::string target) override {
     return virtualize(backend->createSymlink(target), this);
   }
+
+  bool isAbsolutePath(std::string_view path) override {
+    return path.front() == '/';
+  }
+
+  std::string getRootPath(std::string_view abs_path) override {
+    return "/";
+  }
 };
 
 // Create an ignore case backend by supplying another backend.
diff --git a/system/lib/wasmfs/backends/memory_backend.cpp b/system/lib/wasmfs/backends/memory_backend.cpp
index 6752b3bbbb5bd..5c9ffa4a33582 100644
--- a/system/lib/wasmfs/backends/memory_backend.cpp
+++ b/system/lib/wasmfs/backends/memory_backend.cpp
@@ -104,6 +104,12 @@ class MemoryBackend : public Backend {
   std::shared_ptr<Symlink> createSymlink(std::string target) override {
     return std::make_shared<MemorySymlink>(target, this);
   }
+  bool isAbsolutePath(std::string_view path) override {
+    return path.front() == '/';
+  }
+  std::string getRootPath(std::string_view abs_path) override {
+    return "/";
+  }
 };
 
 backend_t createMemoryBackend() {
diff --git a/system/lib/wasmfs/backends/node_backend.cpp b/system/lib/wasmfs/backends/node_backend.cpp
index 5daabd5556055..d54704c5ad004 100644
--- a/system/lib/wasmfs/backends/node_backend.cpp
+++ b/system/lib/wasmfs/backends/node_backend.cpp
@@ -296,6 +296,19 @@ class NodeBackend : public Backend {
   std::shared_ptr<Symlink> createSymlink(std::string target) override {
     WASMFS_UNREACHABLE("TODO: implement NodeBackend::createSymlink");
   }
+
+  bool isAbsolutePath(std::string_view path) override {
+    return _wasmfs_node_path_is_abs(std::string(path).c_str());
+  }
+
+  std::string getRootPath(std::string_view abs_path) override {
+    char buf[PATH_MAX];
+    auto path = std::string(abs_path);
+    if (_wasmfs_node_path_get_root(path.c_str(), buf, PATH_MAX) < 0) {
+      WASMFS_UNREACHABLE("getRootPath cannot fail");
+    }
+    return std::string(buf);
+  }
 };
 
 // TODO: symlink
diff --git a/system/lib/wasmfs/backends/node_backend.h b/system/lib/wasmfs/backends/node_backend.h
index 7e6e496b7c73f..ca276e8d2de89 100644
--- a/system/lib/wasmfs/backends/node_backend.h
+++ b/system/lib/wasmfs/backends/node_backend.h
@@ -52,4 +52,7 @@ int _wasmfs_node_read(
 int _wasmfs_node_write(
   int fd, const void* buf, uint32_t len, uint32_t pos, uint32_t* nwritten);
 
+int _wasmfs_node_path_is_abs(const char* path);
+int _wasmfs_node_path_get_root(const char* abs_path, const char *buf, int bufsize);
+
 } // extern "C"
diff --git a/system/lib/wasmfs/backends/opfs_backend.cpp b/system/lib/wasmfs/backends/opfs_backend.cpp
index f5a014f5d83b5..32c3432cbc054 100644
--- a/system/lib/wasmfs/backends/opfs_backend.cpp
+++ b/system/lib/wasmfs/backends/opfs_backend.cpp
@@ -393,6 +393,14 @@ class OPFSBackend : public Backend {
     // Symlinks not supported.
     return nullptr;
   }
+
+  bool isAbsolutePath(std::string_view path) override {
+    return path.front() == '/';
+  }
+
+  std::string getRootPath(std::string_view abs_path) override {
+    return "/";
+  }
 };
 
 } // anonymous namespace
diff --git a/system/lib/wasmfs/js_impl_backend.h b/system/lib/wasmfs/js_impl_backend.h
index 38d4b59c61bdc..2a638baefef6e 100644
--- a/system/lib/wasmfs/js_impl_backend.h
+++ b/system/lib/wasmfs/js_impl_backend.h
@@ -120,6 +120,12 @@ class JSImplBackend : public Backend {
   std::shared_ptr<Symlink> createSymlink(std::string target) override {
     return std::make_shared<MemorySymlink>(target, this);
   }
+  bool isAbsolutePath(std::string_view path) override {
+    return path.front() == '/';
+  }
+  std::string getRootPath(std::string_view abs_path) override {
+    return "/";
+  }
 };
 
 extern "C" {
diff --git a/system/lib/wasmfs/paths.cpp b/system/lib/wasmfs/paths.cpp
index 3d1fbf4c081e8..6033c996cf291 100644
--- a/system/lib/wasmfs/paths.cpp
+++ b/system/lib/wasmfs/paths.cpp
@@ -69,10 +69,12 @@ ParsedParent doParseParent(std::string_view path,
     return {-ENOENT};
   }
 
+  auto currBackend = curr->getBackend();
+
   // Handle absolute paths.
-  if (path.front() == '/') {
+  if (currBackend->isAbsolutePath(path)) {
     curr = wasmFS.getRootDirectory();
-    path.remove_prefix(1);
+    path.remove_prefix(currBackend->getRootPath(path).size());
   }
 
   // Ignore trailing '/'.
diff --git a/system/lib/wasmfs/proxied_async_js_impl_backend.h b/system/lib/wasmfs/proxied_async_js_impl_backend.h
index e91ec561ef5ff..0c603244b394b 100644
--- a/system/lib/wasmfs/proxied_async_js_impl_backend.h
+++ b/system/lib/wasmfs/proxied_async_js_impl_backend.h
@@ -161,6 +161,14 @@ class ProxiedAsyncJSBackend : public Backend {
   std::shared_ptr<Symlink> createSymlink(std::string target) override {
     return std::make_shared<MemorySymlink>(target, this);
   }
+
+  bool isAbsolutePath(std::string_view path) override {
+    return path.front() == '/';
+  }
+
+  std::string getRootPath(std::string_view abs_path) override {
+    return "/";
+  }
 };
 
 } // namespace wasmfs

From 4e6a56848ea772aa267399b279d1053d7a4c63ca Mon Sep 17 00:00:00 2001
From: Kleis Auke Wolthuizen <github@kleisauke.nl>
Date: Tue, 24 Mar 2026 10:26:46 +0100
Subject: [PATCH 3/7] Simplify

---
 src/lib/libsigs.js                                 |  1 +
 src/lib/libwasmfs_node.js                          |  9 ++-------
 system/lib/wasmfs/backend.h                        |  3 +--
 system/lib/wasmfs/backends/ignore_case_backend.cpp |  8 ++------
 system/lib/wasmfs/backends/memory_backend.cpp      |  7 ++-----
 system/lib/wasmfs/backends/node_backend.cpp        | 10 +++-------
 system/lib/wasmfs/backends/node_backend.h          |  3 +--
 system/lib/wasmfs/backends/opfs_backend.cpp        |  8 ++------
 system/lib/wasmfs/js_impl_backend.h                |  7 ++-----
 system/lib/wasmfs/paths.cpp                        |  6 +++---
 system/lib/wasmfs/proxied_async_js_impl_backend.h  |  8 ++------
 test/test_other.py                                 |  4 +++-
 12 files changed, 24 insertions(+), 50 deletions(-)

diff --git a/src/lib/libsigs.js b/src/lib/libsigs.js
index bb990b3f9c142..7182a4733b380 100644
--- a/src/lib/libsigs.js
+++ b/src/lib/libsigs.js
@@ -411,6 +411,7 @@ sigs = {
   _wasmfs_node_insert_directory__sig: 'ipi',
   _wasmfs_node_insert_file__sig: 'ipi',
   _wasmfs_node_open__sig: 'ipp',
+  _wasmfs_node_path_get_root__sig: 'ippi',
   _wasmfs_node_read__sig: 'iipiip',
   _wasmfs_node_readdir__sig: 'ipp',
   _wasmfs_node_readlink__sig: 'ippi',
diff --git a/src/lib/libwasmfs_node.js b/src/lib/libwasmfs_node.js
index ff94b68a77458..62a099734f094 100644
--- a/src/lib/libwasmfs_node.js
+++ b/src/lib/libwasmfs_node.js
@@ -224,14 +224,9 @@ addToLibrary({
     });
   },
 
-  _wasmfs_node_path_is_abs__deps: ['$nodePath'],
-  _wasmfs_node_path_is_abs: (path_p) => {
-    return nodePath.isAbsolute(UTF8ToString(path_p));
-  },
-
   _wasmfs_node_path_get_root__deps: ['$nodePath'],
-  _wasmfs_node_path_get_root: (abs_path_p, target_p, bufsize) => {
-    return stringToUTF8(nodePath.parse(UTF8ToString(abs_path_p)).root, target_p, bufsize);
+  _wasmfs_node_path_get_root: (path_p, target_p, bufsize) => {
+    return stringToUTF8(nodePath.parse(UTF8ToString(path_p)).root, target_p, bufsize);
   },
 
 });
diff --git a/system/lib/wasmfs/backend.h b/system/lib/wasmfs/backend.h
index 31761a37764d5..6b96189464f5e 100644
--- a/system/lib/wasmfs/backend.h
+++ b/system/lib/wasmfs/backend.h
@@ -21,8 +21,7 @@ class Backend {
   virtual std::shared_ptr<Directory> createDirectory(mode_t mode) = 0;
   virtual std::shared_ptr<Symlink> createSymlink(std::string target) = 0;
 
-  virtual bool isAbsolutePath(std::string_view path) = 0;
-  virtual std::string getRootPath(std::string_view abs_path) = 0;
+  virtual std::string getRootPath(std::string_view path) = 0;
 
   virtual ~Backend() = default;
 };
diff --git a/system/lib/wasmfs/backends/ignore_case_backend.cpp b/system/lib/wasmfs/backends/ignore_case_backend.cpp
index 46540ddf438e0..992f9f4788d06 100644
--- a/system/lib/wasmfs/backends/ignore_case_backend.cpp
+++ b/system/lib/wasmfs/backends/ignore_case_backend.cpp
@@ -226,12 +226,8 @@ class IgnoreCaseBackend : public Backend {
     return virtualize(backend->createSymlink(target), this);
   }
 
-  bool isAbsolutePath(std::string_view path) override {
-    return path.front() == '/';
-  }
-
-  std::string getRootPath(std::string_view abs_path) override {
-    return "/";
+  std::string getRootPath(std::string_view path) override {
+    return path.front() == '/' ? "/" : "";
   }
 };
 
diff --git a/system/lib/wasmfs/backends/memory_backend.cpp b/system/lib/wasmfs/backends/memory_backend.cpp
index 5c9ffa4a33582..975d0ccf8cf3f 100644
--- a/system/lib/wasmfs/backends/memory_backend.cpp
+++ b/system/lib/wasmfs/backends/memory_backend.cpp
@@ -104,11 +104,8 @@ class MemoryBackend : public Backend {
   std::shared_ptr<Symlink> createSymlink(std::string target) override {
     return std::make_shared<MemorySymlink>(target, this);
   }
-  bool isAbsolutePath(std::string_view path) override {
-    return path.front() == '/';
-  }
-  std::string getRootPath(std::string_view abs_path) override {
-    return "/";
+  std::string getRootPath(std::string_view path) override {
+    return path.front() == '/' ? "/" : "";
   }
 };
 
diff --git a/system/lib/wasmfs/backends/node_backend.cpp b/system/lib/wasmfs/backends/node_backend.cpp
index d54704c5ad004..73776adb434f4 100644
--- a/system/lib/wasmfs/backends/node_backend.cpp
+++ b/system/lib/wasmfs/backends/node_backend.cpp
@@ -297,14 +297,10 @@ class NodeBackend : public Backend {
     WASMFS_UNREACHABLE("TODO: implement NodeBackend::createSymlink");
   }
 
-  bool isAbsolutePath(std::string_view path) override {
-    return _wasmfs_node_path_is_abs(std::string(path).c_str());
-  }
-
-  std::string getRootPath(std::string_view abs_path) override {
+  std::string getRootPath(std::string_view path) override {
     char buf[PATH_MAX];
-    auto path = std::string(abs_path);
-    if (_wasmfs_node_path_get_root(path.c_str(), buf, PATH_MAX) < 0) {
+    auto pathStr = std::string(path);
+    if (_wasmfs_node_path_get_root(pathStr.c_str(), buf, PATH_MAX) < 0) {
       WASMFS_UNREACHABLE("getRootPath cannot fail");
     }
     return std::string(buf);
diff --git a/system/lib/wasmfs/backends/node_backend.h b/system/lib/wasmfs/backends/node_backend.h
index ca276e8d2de89..f8318c940d16d 100644
--- a/system/lib/wasmfs/backends/node_backend.h
+++ b/system/lib/wasmfs/backends/node_backend.h
@@ -52,7 +52,6 @@ int _wasmfs_node_read(
 int _wasmfs_node_write(
   int fd, const void* buf, uint32_t len, uint32_t pos, uint32_t* nwritten);
 
-int _wasmfs_node_path_is_abs(const char* path);
-int _wasmfs_node_path_get_root(const char* abs_path, const char *buf, int bufsize);
+int _wasmfs_node_path_get_root(const char* path, const char *buf, int bufsize);
 
 } // extern "C"
diff --git a/system/lib/wasmfs/backends/opfs_backend.cpp b/system/lib/wasmfs/backends/opfs_backend.cpp
index 32c3432cbc054..81287d49003d6 100644
--- a/system/lib/wasmfs/backends/opfs_backend.cpp
+++ b/system/lib/wasmfs/backends/opfs_backend.cpp
@@ -394,12 +394,8 @@ class OPFSBackend : public Backend {
     return nullptr;
   }
 
-  bool isAbsolutePath(std::string_view path) override {
-    return path.front() == '/';
-  }
-
-  std::string getRootPath(std::string_view abs_path) override {
-    return "/";
+  std::string getRootPath(std::string_view path) override {
+    return path.front() == '/' ? "/" : "";
   }
 };
 
diff --git a/system/lib/wasmfs/js_impl_backend.h b/system/lib/wasmfs/js_impl_backend.h
index 2a638baefef6e..a2b5cd425faa8 100644
--- a/system/lib/wasmfs/js_impl_backend.h
+++ b/system/lib/wasmfs/js_impl_backend.h
@@ -120,11 +120,8 @@ class JSImplBackend : public Backend {
   std::shared_ptr<Symlink> createSymlink(std::string target) override {
     return std::make_shared<MemorySymlink>(target, this);
   }
-  bool isAbsolutePath(std::string_view path) override {
-    return path.front() == '/';
-  }
-  std::string getRootPath(std::string_view abs_path) override {
-    return "/";
+  std::string getRootPath(std::string_view path) override {
+    return path.front() == '/' ? "/" : "";
   }
 };
 
diff --git a/system/lib/wasmfs/paths.cpp b/system/lib/wasmfs/paths.cpp
index 6033c996cf291..8262d12b3003a 100644
--- a/system/lib/wasmfs/paths.cpp
+++ b/system/lib/wasmfs/paths.cpp
@@ -69,12 +69,12 @@ ParsedParent doParseParent(std::string_view path,
     return {-ENOENT};
   }
 
-  auto currBackend = curr->getBackend();
+  auto rootPath = curr->getBackend()->getRootPath(path);
 
   // Handle absolute paths.
-  if (currBackend->isAbsolutePath(path)) {
+  if (!rootPath.empty()) {
     curr = wasmFS.getRootDirectory();
-    path.remove_prefix(currBackend->getRootPath(path).size());
+    path.remove_prefix(rootPath.size());
   }
 
   // Ignore trailing '/'.
diff --git a/system/lib/wasmfs/proxied_async_js_impl_backend.h b/system/lib/wasmfs/proxied_async_js_impl_backend.h
index 0c603244b394b..aab1b95ebaffc 100644
--- a/system/lib/wasmfs/proxied_async_js_impl_backend.h
+++ b/system/lib/wasmfs/proxied_async_js_impl_backend.h
@@ -162,12 +162,8 @@ class ProxiedAsyncJSBackend : public Backend {
     return std::make_shared<MemorySymlink>(target, this);
   }
 
-  bool isAbsolutePath(std::string_view path) override {
-    return path.front() == '/';
-  }
-
-  std::string getRootPath(std::string_view abs_path) override {
-    return "/";
+  std::string getRootPath(std::string_view path) override {
+    return path.front() == '/' ? "/" : "";
   }
 };
 
diff --git a/test/test_other.py b/test/test_other.py
index 7c33c07af1f1b..a82139b75e735 100644
--- a/test/test_other.py
+++ b/test/test_other.py
@@ -13827,7 +13827,9 @@ def test_fs_icase(self):
   @crossplatform
   @with_all_fs
   def test_std_filesystem(self):
-    self.do_other_test('test_std_filesystem.cpp')
+    # build with `-fexceptions` to catch `filesystem_error`. Otherwise, the follwing exception may occur:
+    # "filesystem_error was thrown in -fno-exceptions mode"
+    self.do_other_test('test_std_filesystem.cpp', cflags=['-fexceptions'])
 
   @crossplatform
   @with_all_fs

From 7263eff3a1ad2ce2e512449d13c4853e6201bdd9 Mon Sep 17 00:00:00 2001
From: Kleis Auke Wolthuizen <github@kleisauke.nl>
Date: Tue, 24 Mar 2026 11:18:12 +0100
Subject: [PATCH 4/7] [WiP] Try to fix Windows CI (2)

---
 src/lib/libwasmfs_node.js          | 2 +-
 test/other/test_std_filesystem.cpp | 2 +-
 2 files changed, 2 insertions(+), 2 deletions(-)

diff --git a/src/lib/libwasmfs_node.js b/src/lib/libwasmfs_node.js
index 62a099734f094..74ce3858118bd 100644
--- a/src/lib/libwasmfs_node.js
+++ b/src/lib/libwasmfs_node.js
@@ -5,7 +5,7 @@
  */
 
 addToLibrary({
-  $wasmfsNodeIsWindows: !!process.platform.match(/^win/),
+  $wasmfsNodeIsWindows: "!!process.platform.match(/^win/)",
   $nodePath: "require('node:path')",
 
   $wasmfsNodeConvertNodeCode__deps: ['$ERRNO_CODES'],
diff --git a/test/other/test_std_filesystem.cpp b/test/other/test_std_filesystem.cpp
index 41cc2275d08d4..894a129bdf5f7 100644
--- a/test/other/test_std_filesystem.cpp
+++ b/test/other/test_std_filesystem.cpp
@@ -13,7 +13,7 @@ int main() {
   std::cout << "remove(): " << fs::remove(tmp / foo) << '\n'; // success
   std::cout << "remove(): " << fs::remove(tmp / foo) << '\n'; // fail
 
-  std::filesystem::create_directories(tmp / "abcdef/example");
+  std::filesystem::create_directories(tmp / "abcdef" / "example");
   const std::uintmax_t n{fs::remove_all(tmp / "abcdef")};
   std::cout << "remove_all(): " << n << " files or directories\n";
 }

From fd7f0a9258b8d2ca8086e7c737d08fead27ddbc8 Mon Sep 17 00:00:00 2001
From: Kleis Auke Wolthuizen <github@kleisauke.nl>
Date: Tue, 24 Mar 2026 11:24:04 +0100
Subject: [PATCH 5/7] [WiP] Try to fix Closure when building with
 `-sENVIRONMENT=web`

Details:
```
building:ERROR: Closure compiler run failed:

building:ERROR: /tmp/emscripten_temp_j4p9p4rt/vips-es6.jso3.js:5791:28: ERROR - [JSC_UNDEFINED_VARIABLE] variable process is undeclared
  5791| var wasmfsNodeIsWindows = !!process.platform.match(/^win/);
                                    ^^^^^^^

building:ERROR: /tmp/emscripten_temp_j4p9p4rt/vips-es6.jso3.js:6006:15: ERROR - [JSC_UNDEFINED_VARIABLE] variable require is undeclared
  6006| var nodePath = require("node:path");
                       ^^^^^^^

2 error(s), 0 warning(s)
```
---
 src/lib/libwasmfs_node.js | 28 ++++++++++++++++++++++++----
 test/test_other.py        | 25 +++++++++++++++++++++++++
 2 files changed, 49 insertions(+), 4 deletions(-)

diff --git a/src/lib/libwasmfs_node.js b/src/lib/libwasmfs_node.js
index 74ce3858118bd..475c0e4880674 100644
--- a/src/lib/libwasmfs_node.js
+++ b/src/lib/libwasmfs_node.js
@@ -5,8 +5,28 @@
  */
 
 addToLibrary({
-  $wasmfsNodeIsWindows: "!!process.platform.match(/^win/)",
-  $nodePath: "require('node:path')",
+#if !ENVIRONMENT_MAY_BE_NODE
+  _wasmfs_node_readdir: (path_p, vec) => {},
+  _wasmfs_node_get_mode: (path_p, mode_p) => {},
+  _wasmfs_node_stat_size: (path_p, size_p) => {},
+  _wasmfs_node_fstat_size: (fd, size_p) => {},
+  _wasmfs_node_insert_file: (path_p, mode) => {},
+  _wasmfs_node_insert_directory: (path_p, mode) => {},
+  _wasmfs_node_unlink: (path_p) => {},
+  _wasmfs_node_rmdir: (path_p) => {},
+  _wasmfs_node_truncate: (path_p, len) => {},
+  _wasmfs_node_ftruncate: (fd, len) => {},
+  _wasmfs_node_open: (path_p, mode_p) => {},
+  _wasmfs_node_rename: (from_path_p, to_path_p) => {},
+  _wasmfs_node_symlink: (target_path_p, linkpath_path_p) => {},
+  _wasmfs_node_readlink: (path_p, target_p, bufsize) => {},
+  _wasmfs_node_close: (fd) => {},
+  _wasmfs_node_read: (fd, buf_p, len, pos, nread_p) => {},
+  _wasmfs_node_write: (fd, buf_p, len, pos, nwritten_p) => {},
+  _wasmfs_node_path_get_root: (path_p, target_p, bufsize) => {},
+#else
+  $wasmfsNodeIsWindows: "!!globalThis.process?.platform.match(/^win/)",
+  $nodePath: "ENVIRONMENT_IS_NODE ? require('node:path') : undefined",
 
   $wasmfsNodeConvertNodeCode__deps: ['$ERRNO_CODES'],
   $wasmfsNodeConvertNodeCode: (e) => {
@@ -194,7 +214,7 @@ addToLibrary({
     });
   },
 
-  _wasmfs_node_close__deps: [],
+  _wasmfs_node_close__deps: ['$wasmfsTry'],
   _wasmfs_node_close: (fd) => {
     return wasmfsTry(() => {
       fs.closeSync(fd);
@@ -228,5 +248,5 @@ addToLibrary({
   _wasmfs_node_path_get_root: (path_p, target_p, bufsize) => {
     return stringToUTF8(nodePath.parse(UTF8ToString(path_p)).root, target_p, bufsize);
   },
-
+#endif
 });
diff --git a/test/test_other.py b/test/test_other.py
index a82139b75e735..fea596148b975 100644
--- a/test/test_other.py
+++ b/test/test_other.py
@@ -9292,6 +9292,31 @@ def test_noderawfs_open_abspath(self):
     ''')
     self.do_runf('open.c', cflags=['-sNODERAWFS'], args=[os.path.abspath('foo')])
 
+  def test_wasmfs_nodefs_stubs(self):
+    # This is essentially equivalent to building with `-sWASMFS -sNODERAWFS`, except that
+    # the Wasm binary can also be used on the web. Ensure that this use case is supported.
+    create_file('main.c', r'''
+      #include <emscripten/emscripten.h>
+      #include <emscripten/wasmfs.h>
+
+      EM_JS(bool, is_node, (), { return ENVIRONMENT_IS_NODE; });
+
+      backend_t wasmfs_create_root_dir() {
+          return is_node() ? wasmfs_create_node_backend("")
+                           : wasmfs_create_memory_backend();
+      }
+
+      backend_t wasmfs_create_working_dir(backend_t root_backend) {
+          return is_node() ? wasmfs_create_node_backend(".")
+                           : root_backend;
+      }
+
+      int main(int argc, char** argv) {
+        return 0;
+      }
+    ''')
+    self.run_process([EMCC, 'main.c', '-sWASMFS', '-sENVIRONMENT=web'])
+
   def test_noderawfs_readfile_prerun(self):
     create_file('foo', 'bar')
     self.add_pre_run("console.log(FS.readFile('foo', { encoding: 'utf8' }));")

From 3751c1b13f05b06b7559e86f953f301555f74fc2 Mon Sep 17 00:00:00 2001
From: Kleis Auke Wolthuizen <github@kleisauke.nl>
Date: Tue, 24 Mar 2026 13:54:33 +0100
Subject: [PATCH 6/7] Revert debugging

---
 system/lib/wasmfs/backends/node_backend.cpp | 2 +-
 test/other/test_std_filesystem.cpp          | 2 +-
 test/test_other.py                          | 6 +++---
 3 files changed, 5 insertions(+), 5 deletions(-)

diff --git a/system/lib/wasmfs/backends/node_backend.cpp b/system/lib/wasmfs/backends/node_backend.cpp
index 73776adb434f4..24e78bc63d6a7 100644
--- a/system/lib/wasmfs/backends/node_backend.cpp
+++ b/system/lib/wasmfs/backends/node_backend.cpp
@@ -191,7 +191,7 @@ class NodeDirectory : public Directory {
     if (_wasmfs_node_get_mode(childPath.c_str(), &mode)) {
       return nullptr;
     }
-    // Allow reading from character device files (e.g. `/dev/random`,
+    // Allow reading from character device files too (e.g. `/dev/random`,
     // `/dev/urandom`)
     if (S_ISREG(mode) || S_ISCHR(mode)) {
       return std::make_shared<NodeFile>(mode, getBackend(), childPath);
diff --git a/test/other/test_std_filesystem.cpp b/test/other/test_std_filesystem.cpp
index 894a129bdf5f7..41cc2275d08d4 100644
--- a/test/other/test_std_filesystem.cpp
+++ b/test/other/test_std_filesystem.cpp
@@ -13,7 +13,7 @@ int main() {
   std::cout << "remove(): " << fs::remove(tmp / foo) << '\n'; // success
   std::cout << "remove(): " << fs::remove(tmp / foo) << '\n'; // fail
 
-  std::filesystem::create_directories(tmp / "abcdef" / "example");
+  std::filesystem::create_directories(tmp / "abcdef/example");
   const std::uintmax_t n{fs::remove_all(tmp / "abcdef")};
   std::cout << "remove_all(): " << n << " files or directories\n";
 }
diff --git a/test/test_other.py b/test/test_other.py
index fea596148b975..5c58c4afe378e 100644
--- a/test/test_other.py
+++ b/test/test_other.py
@@ -13852,9 +13852,9 @@ def test_fs_icase(self):
   @crossplatform
   @with_all_fs
   def test_std_filesystem(self):
-    # build with `-fexceptions` to catch `filesystem_error`. Otherwise, the follwing exception may occur:
-    # "filesystem_error was thrown in -fno-exceptions mode"
-    self.do_other_test('test_std_filesystem.cpp', cflags=['-fexceptions'])
+    if (WINDOWS or MACOS) and self.get_setting('NODERAWFS') and self.get_setting('WASMFS'):
+      self.skipTest('fails with ENOTEMPTY (Directory not empty) during fs::remove_all')
+    self.do_other_test('test_std_filesystem.cpp')
 
   @crossplatform
   @with_all_fs

From 1c4adc86ae40564b6364df0636f465801822a0c4 Mon Sep 17 00:00:00 2001
From: Kleis Auke Wolthuizen <github@kleisauke.nl>
Date: Tue, 24 Mar 2026 20:10:45 +0100
Subject: [PATCH 7/7] Simplify

---
 system/lib/wasmfs/backend.h                        | 4 +++-
 system/lib/wasmfs/backends/ignore_case_backend.cpp | 4 ----
 system/lib/wasmfs/backends/memory_backend.cpp      | 3 ---
 system/lib/wasmfs/backends/opfs_backend.cpp        | 4 ----
 system/lib/wasmfs/js_impl_backend.h                | 3 ---
 system/lib/wasmfs/proxied_async_js_impl_backend.h  | 4 ----
 6 files changed, 3 insertions(+), 19 deletions(-)

diff --git a/system/lib/wasmfs/backend.h b/system/lib/wasmfs/backend.h
index 6b96189464f5e..18a9c305d322d 100644
--- a/system/lib/wasmfs/backend.h
+++ b/system/lib/wasmfs/backend.h
@@ -21,7 +21,9 @@ class Backend {
   virtual std::shared_ptr<Directory> createDirectory(mode_t mode) = 0;
   virtual std::shared_ptr<Symlink> createSymlink(std::string target) = 0;
 
-  virtual std::string getRootPath(std::string_view path) = 0;
+  virtual std::string getRootPath(std::string_view path) {
+    return path.front() == '/' ? "/" : "";
+  }
 
   virtual ~Backend() = default;
 };
diff --git a/system/lib/wasmfs/backends/ignore_case_backend.cpp b/system/lib/wasmfs/backends/ignore_case_backend.cpp
index 992f9f4788d06..ba1f1f4e0b72a 100644
--- a/system/lib/wasmfs/backends/ignore_case_backend.cpp
+++ b/system/lib/wasmfs/backends/ignore_case_backend.cpp
@@ -225,10 +225,6 @@ class IgnoreCaseBackend : public Backend {
   std::shared_ptr<Symlink> createSymlink(std::string target) override {
     return virtualize(backend->createSymlink(target), this);
   }
-
-  std::string getRootPath(std::string_view path) override {
-    return path.front() == '/' ? "/" : "";
-  }
 };
 
 // Create an ignore case backend by supplying another backend.
diff --git a/system/lib/wasmfs/backends/memory_backend.cpp b/system/lib/wasmfs/backends/memory_backend.cpp
index 975d0ccf8cf3f..6752b3bbbb5bd 100644
--- a/system/lib/wasmfs/backends/memory_backend.cpp
+++ b/system/lib/wasmfs/backends/memory_backend.cpp
@@ -104,9 +104,6 @@ class MemoryBackend : public Backend {
   std::shared_ptr<Symlink> createSymlink(std::string target) override {
     return std::make_shared<MemorySymlink>(target, this);
   }
-  std::string getRootPath(std::string_view path) override {
-    return path.front() == '/' ? "/" : "";
-  }
 };
 
 backend_t createMemoryBackend() {
diff --git a/system/lib/wasmfs/backends/opfs_backend.cpp b/system/lib/wasmfs/backends/opfs_backend.cpp
index 81287d49003d6..f5a014f5d83b5 100644
--- a/system/lib/wasmfs/backends/opfs_backend.cpp
+++ b/system/lib/wasmfs/backends/opfs_backend.cpp
@@ -393,10 +393,6 @@ class OPFSBackend : public Backend {
     // Symlinks not supported.
     return nullptr;
   }
-
-  std::string getRootPath(std::string_view path) override {
-    return path.front() == '/' ? "/" : "";
-  }
 };
 
 } // anonymous namespace
diff --git a/system/lib/wasmfs/js_impl_backend.h b/system/lib/wasmfs/js_impl_backend.h
index a2b5cd425faa8..38d4b59c61bdc 100644
--- a/system/lib/wasmfs/js_impl_backend.h
+++ b/system/lib/wasmfs/js_impl_backend.h
@@ -120,9 +120,6 @@ class JSImplBackend : public Backend {
   std::shared_ptr<Symlink> createSymlink(std::string target) override {
     return std::make_shared<MemorySymlink>(target, this);
   }
-  std::string getRootPath(std::string_view path) override {
-    return path.front() == '/' ? "/" : "";
-  }
 };
 
 extern "C" {
diff --git a/system/lib/wasmfs/proxied_async_js_impl_backend.h b/system/lib/wasmfs/proxied_async_js_impl_backend.h
index aab1b95ebaffc..e91ec561ef5ff 100644
--- a/system/lib/wasmfs/proxied_async_js_impl_backend.h
+++ b/system/lib/wasmfs/proxied_async_js_impl_backend.h
@@ -161,10 +161,6 @@ class ProxiedAsyncJSBackend : public Backend {
   std::shared_ptr<Symlink> createSymlink(std::string target) override {
     return std::make_shared<MemorySymlink>(target, this);
   }
-
-  std::string getRootPath(std::string_view path) override {
-    return path.front() == '/' ? "/" : "";
-  }
 };
 
 } // namespace wasmfs