Skip to content

[WasmFS] Skip mounting special files under NODERAWFS #26607

New issue

Have a question about this project? Sign up for a free GitHub account to open an issue and contact its maintainers and the community.

Sign up for GitHub

By clicking “Sign up for GitHub”, you agree to our terms of service and privacy statement. We’ll occasionally send you account related emails.

Already on GitHub? Sign in to your account

Open
kleisauke wants to merge 3 commits into
base: main
Choose a base branch
from
Open

[WasmFS] Skip mounting special files under NODERAWFS #26607

Show file tree
Hide file tree
Changes from 2 commits
Commits
Show all changes
3 commits
Select commit Hold shift + click to select a range
50159b1
[WasmFS] Skip mounting special files under NODERAWFS
kleisauke Mar 25, 2026
e1da2f5
Automatic rebaseline of codesize expectations. NFC
kleisauke Apr 2, 2026
f3b85c9
Incorporate feedback
kleisauke Apr 2, 2026
File filter

Filter by extension

Filter by extension
Conversations
Failed to load comments.
Loading
Jump to
Jump to file
Failed to load files.
Loading
Diff view
Diff view
2 changes: 2 additions & 0 deletions system/lib/wasmfs/backend.h
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -21,6 +21,8 @@ class Backend {
virtual std::shared_ptr<Directory> createDirectory(mode_t mode) = 0;
virtual std::shared_ptr<Symlink> createSymlink(std::string target) = 0;

virtual bool shouldMountSpecialFiles() { return true; }
Copy link
Copy Markdown
Collaborator

@sbc100 sbc100 Apr 2, 2026

Choose a reason for hiding this comment

The reason will be displayed to describe this comment to others. Learn more.

I was thinking maybe shouldPopulateRoot, but maybe your name is more explicit?

Copy link
Copy Markdown
Collaborator Author

@kleisauke kleisauke Apr 2, 2026

Choose a reason for hiding this comment

The reason will be displayed to describe this comment to others. Learn more.

This function name was mentioned in comment #24733 (comment). But I'd like shouldPopulateRoot as well.


virtual ~Backend() = default;
};

Expand Down
2 changes: 2 additions & 0 deletions system/lib/wasmfs/backends/node_backend.cpp
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -294,6 +294,8 @@ class NodeBackend : public Backend {
std::shared_ptr<Symlink> createSymlink(std::string target) override {
WASMFS_UNREACHABLE("TODO: implement NodeBackend::createSymlink");
}

virtual bool shouldMountSpecialFiles() override { return false; }
};

// TODO: symlink
Expand Down
7 changes: 6 additions & 1 deletion system/lib/wasmfs/wasmfs.cpp
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -106,8 +106,13 @@ std::shared_ptr<Directory> WasmFS::initRootDirectory() {
// The root directory is its own parent.
lockedRoot.setParent(rootDirectory);

// Don't mount special files if not needed (e.g. in NODERAWFS mode).
if (!rootBackend->shouldMountSpecialFiles()) {
return rootDirectory;
}

// If the /dev/ directory does not already exist, create it. (It may already
// exist in NODERAWFS mode, or if those files have been preloaded.)
// exist if those files have been preloaded.)
auto devDir = lockedRoot.insertDirectory("dev", S_IRUGO | S_IXUGO);
if (devDir) {
auto lockedDev = devDir->locked();
Expand Down
8 changes: 4 additions & 4 deletions test/codesize/test_codesize_cxx_wasmfs.json
View file
Open in desktop
Original file line number Diff line number Diff line change
@@ -1,10 +1,10 @@
{
"a.out.js": 7023,
"a.out.js.gz": 3310,
"a.out.nodebug.wasm": 172714,
"a.out.nodebug.wasm.gz": 63316,
"total": 179737,
"total_gz": 66626,
"a.out.nodebug.wasm": 172741,
"a.out.nodebug.wasm.gz": 63348,
"total": 179764,
"total_gz": 66658,
"sent": [
"__cxa_throw",
"_abort_js",
Expand Down
8 changes: 4 additions & 4 deletions test/codesize/test_codesize_files_wasmfs.json
View file
Open in desktop
Original file line number Diff line number Diff line change
@@ -1,10 +1,10 @@
{
"a.out.js": 5465,
"a.out.js.gz": 2575,
"a.out.nodebug.wasm": 58418,
"a.out.nodebug.wasm.gz": 18067,
"total": 63883,
"total_gz": 20642,
"a.out.nodebug.wasm": 58443,
"a.out.nodebug.wasm.gz": 18094,
"total": 63908,
"total_gz": 20669,
"sent": [
"a (emscripten_date_now)",
"b (emscripten_err)",
Expand Down
5 changes: 3 additions & 2 deletions test/test_other.py
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -5553,6 +5553,8 @@ def test_fsync(self, args):
def test_fs_dev_random(self):
if WINDOWS and self.get_setting('NODERAWFS'):
self.skipTest('Crashes on Windows and NodeFS')
if self.get_setting('NODERAWFS') and self.get_setting('WASMFS'):
self.skipTest('https://github.com/emscripten-core/emscripten/issues/24830')
self.do_runf('fs/test_fs_dev_random.c', 'success')

@parameterized({
Expand Down Expand Up @@ -13254,11 +13256,10 @@ def test_unistd_chown(self):
self.set_setting('WASMFS')
self.do_run_in_out_file_test('wasmfs/wasmfs_chown.c')

@wasmfs_all_backends
Copy link
Copy Markdown
Collaborator

@sbc100 sbc100 Apr 2, 2026

Choose a reason for hiding this comment

The reason will be displayed to describe this comment to others. Learn more.

Why remove this?

Does wasmfs_getdents.c need to get re-written to handle the rawfs mabye?

Copy link
Copy Markdown
Collaborator

@sbc100 sbc100 Apr 2, 2026

Choose a reason for hiding this comment

The reason will be displayed to describe this comment to others. Learn more.

Should we just skip under NODERAWFS rather than removing wasmfs_all_backends completely?

Copy link
Copy Markdown
Collaborator Author

@kleisauke kleisauke Apr 2, 2026

Choose a reason for hiding this comment

The reason will be displayed to describe this comment to others. Learn more.

I re-added the @wasmfs_all_backends decorator and skipped this only under NODERAWFS with commit f3b85c9.

See for details:

emscripten/test/wasmfs/wasmfs_getdents.out

Lines 51 to 59 in 34f6bcf

------------- Reading from /dev Directory via JS -------------
.
..
null
random
stderr
stdin
stdout
urandom

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')
Expand Down
Loading