From 75f250b705d25408b9b1daa83a85618fa21af32c Mon Sep 17 00:00:00 2001
From: Kleis Auke Wolthuizen <github@kleisauke.nl>
Date: Fri, 3 Apr 2026 13:51:03 +0200
Subject: [PATCH] [WasmFS] Ensure error codes are positive in `_wasmfs_node_*`
 APIs

Follow-up to #26598.
---
 src/lib/libwasmfs_node.js                   | 4 ++--
 system/lib/wasmfs/backends/node_backend.cpp | 4 ++--
 2 files changed, 4 insertions(+), 4 deletions(-)

diff --git a/src/lib/libwasmfs_node.js b/src/lib/libwasmfs_node.js
index 02295c10a164f..5d1271f424009 100644
--- a/src/lib/libwasmfs_node.js
+++ b/src/lib/libwasmfs_node.js
@@ -159,14 +159,14 @@ addToLibrary({
   _wasmfs_node_truncate__i53abi: true,
   _wasmfs_node_truncate__deps : ['$wasmfsTry'],
   _wasmfs_node_truncate : (path_p, len) => {
-    if (isNaN(len)) return -{{{ cDefs.EOVERFLOW }}};
+    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) => {
-    if (isNaN(len)) return -{{{ cDefs.EOVERFLOW }}};
+    if (isNaN(len)) return {{{ cDefs.EOVERFLOW }}};
     return wasmfsTry(() => fs.ftruncateSync(fd, len));
   },
 
diff --git a/system/lib/wasmfs/backends/node_backend.cpp b/system/lib/wasmfs/backends/node_backend.cpp
index b6b95eeb61b40..4bfd0f12cd70a 100644
--- a/system/lib/wasmfs/backends/node_backend.cpp
+++ b/system/lib/wasmfs/backends/node_backend.cpp
@@ -124,9 +124,9 @@ class NodeFile : public DataFile {
 
   int setSize(off_t size) override {
     if (state.isOpen()) {
-      return _wasmfs_node_ftruncate(state.getFD(), size);
+      return -_wasmfs_node_ftruncate(state.getFD(), size);
     }
-    return _wasmfs_node_truncate(state.path.c_str(), size);
+    return -_wasmfs_node_truncate(state.path.c_str(), size);
   }
 
   int open(oflags_t flags) override { return state.open(flags); }