diff --git a/misc/wasm/wasm_exec.js b/misc/wasm/wasm_exec.js
index 9ffa9201e87..3c2c1868679 100644
--- a/misc/wasm/wasm_exec.js
+++ b/misc/wasm/wasm_exec.js
@@ -30,6 +30,12 @@
 		global.fs = require("fs");
 	}
 
+	const enosys = () => {
+		const err = new Error("not implemented");
+		err.code = "ENOSYS";
+		return err;
+	};
+
 	if (!global.fs) {
 		let outputBuf = "";
 		global.fs = {
@@ -45,27 +51,53 @@
 			},
 			write(fd, buf, offset, length, position, callback) {
 				if (offset !== 0 || length !== buf.length || position !== null) {
-					throw new Error("not implemented");
+					callback(enosys());
+					return;
 				}
 				const n = this.writeSync(fd, buf);
 				callback(null, n);
 			},
-			open(path, flags, mode, callback) {
-				const err = new Error("not implemented");
-				err.code = "ENOSYS";
-				callback(err);
-			},
-			read(fd, buffer, offset, length, position, callback) {
-				const err = new Error("not implemented");
-				err.code = "ENOSYS";
-				callback(err);
-			},
-			fsync(fd, callback) {
-				callback(null);
-			},
+			chmod(path, mode, callback) { callback(enosys()); },
+			chown(path, uid, gid, callback) { callback(enosys()); },
+			close(fd, callback) { callback(enosys()); },
+			fchmod(fd, mode, callback) { callback(enosys()); },
+			fchown(fd, uid, gid, callback) { callback(enosys()); },
+			fstat(fd, callback) { callback(enosys()); },
+			fsync(fd, callback) { callback(null); },
+			ftruncate(fd, length, callback) { callback(enosys()); },
+			lchown(path, uid, gid, callback) { callback(enosys()); },
+			link(path, link, callback) { callback(enosys()); },
+			lstat(path, callback) { callback(enosys()); },
+			mkdir(path, perm, callback) { callback(enosys()); },
+			open(path, flags, mode, callback) { callback(enosys()); },
+			read(fd, buffer, offset, length, position, callback) { callback(enosys()); },
+			readdir(path, callback) { callback(enosys()); },
+			readlink(path, callback) { callback(enosys()); },
+			rename(from, to, callback) { callback(enosys()); },
+			rmdir(path, callback) { callback(enosys()); },
+			stat(path, callback) { callback(enosys()); },
+			symlink(path, link, callback) { callback(enosys()); },
+			truncate(path, length, callback) { callback(enosys()); },
+			unlink(path, callback) { callback(enosys()); },
+			utimes(path, atime, mtime, callback) { callback(enosys()); },
 		};
 	}
 
+	if (!global.process) {
+		global.process = {
+			getuid() { return -1; },
+			getgid() { return -1; },
+			geteuid() { return -1; },
+			getegid() { return -1; },
+			getgroups() { throw enosys(); },
+			pid: -1,
+			ppid: -1,
+			umask() { throw enosys(); },
+			cwd() { throw enosys(); },
+			chdir() { throw enosys(); },
+		}
+	}
+
 	if (!global.crypto) {
 		const nodeCrypto = require("crypto");
 		global.crypto = {
diff --git a/src/syscall/syscall_js.go b/src/syscall/syscall_js.go
index 987dd4a7961..dfb4a275e30 100644
--- a/src/syscall/syscall_js.go
+++ b/src/syscall/syscall_js.go
@@ -303,9 +303,10 @@ func Getegid() int {
 	return jsProcess.Call("getegid").Int()
 }
 
-func Getgroups() ([]int, error) {
+func Getgroups() (groups []int, err error) {
+	defer recoverErr(&err)
 	array := jsProcess.Call("getgroups")
-	groups := make([]int, array.Length())
+	groups = make([]int, array.Length())
 	for i := range groups {
 		groups[i] = array.Index(i).Int()
 	}