feat: full NFSv4.2 server and client in pure Go

Assisted-by: GLM 5.3 Flash

internal/nfs4server/nattr_test.go

@@ -0,0 +1,120 @@
+// Copyright (c) 2026 Petr Balvín <opensource@petrbalvin.org> (https://petrbalvin.org)
+// SPDX-License-Identifier: MIT
+
+package nfs4server
+
+import (
+	"testing"
+
+	"sourcedock.dev/petrbalvin/nfs/internal/nfs4"
+	"sourcedock.dev/petrbalvin/nfs/internal/nfsfs"
+	"sourcedock.dev/petrbalvin/nfs/internal/xdr"
+)
+
+// OPENATTR opens the synthetic named attribute directory of a.txt, and
+// CREATE, LOOKUP, READ and REMOVE over it map to the object's extended
+// attributes, RFC 8881 section 5.3.
+func TestNamedAttributes(t *testing.T) {
+	h := testTree(t)
+	sid, seq := newSession(t, h)
+	run := func(s uint32, ops [][]byte) (nfs4.CompoundRes, [][]byte) {
+		t.Helper()
+		all := append([][]byte{nfs4.AppendSequenceArgs(nil, sid, s, 0, defaultSlots-1, true)}, ops...)
+		payload := nfs4.AppendCompoundArgs(nil, "nattr", nfs4.MinorVersion, all)
+		body, ok := h.compound(payload, cred{uid: 0, gid: 0})
+		if !ok {
+			t.Fatal("garbage")
+		}
+		r, bodies, derr := nfs4.DecodeCompoundResBodies(body)
+		if derr != nil {
+			t.Fatalf("decode: %v", derr)
+		}
+		return r, bodies[1:]
+	}
+
+	// OPENATTR on a.txt answers the synthetic directory.
+	seq++
+	res, bodies := run(seq, [][]byte{
+		nfs4.AppendPutRootfh(nil),
+		nfs4.AppendLookup(nil, "a.txt"),
+		nfs4.AppendOpenattrArgs(nil, false),
+		nfs4.AppendGetfh(nil),
+	})
+	if res.Status != nfs4.ErrOK {
+		t.Fatalf("openattr: status %d", res.Status)
+	}
+	dirHandle, derr := xdrDecoder(bodies[3])
+	if derr != nil || len(dirHandle) == 0 {
+		t.Fatalf("dir handle: %v", derr)
+	}
+
+	// CREATE makes the attribute with its initial size, WRITE fills it.
+	seq++
+	res, _ = run(seq, [][]byte{
+		nfs4.AppendPutfh(nil, dirHandle),
+		nfs4.AppendCreateArgs(nil, nfs4.NF4Reg, "user.comment", "", 0, 0,
+			0o644),
+	})
+	wantStatus(t, "nattr create", res.Status, nfs4.ErrOK)
+	seq++
+	res, bodies = run(seq, [][]byte{
+		nfs4.AppendPutfh(nil, dirHandle),
+		nfs4.AppendLookup(nil, "user.comment"),
+		nfs4.AppendGetfh(nil),
+	})
+	wantStatus(t, "nattr lookup", res.Status, nfs4.ErrOK)
+	fileHandle, derr := xdrDecoder(bodies[2])
+	if derr != nil {
+		t.Fatal(derr)
+	}
+	seq++
+	res, _ = run(seq, [][]byte{
+		nfs4.AppendPutfh(nil, fileHandle),
+		nfs4.AppendWriteArgs(nil, nfs4.Stateid{}, 0, nfs4.StableFileSync, []byte("hello")),
+	})
+	if res.Status != nfs4.ErrOK {
+		t.Fatalf("nattr write: status %d", res.Status)
+	}
+	seq++
+	res, bodies = run(seq, [][]byte{
+		nfs4.AppendPutfh(nil, fileHandle),
+		nfs4.AppendReadArgs(nil, nfs4.Stateid{}, 0, 64),
+	})
+	if res.Status != nfs4.ErrOK {
+		t.Fatalf("nattr read: status %d", res.Status)
+	}
+	rd := xdr.NewDecoder(bodies[1])
+	if eof, rerr := rd.Bool(); rerr != nil || !eof {
+		t.Fatalf("eof %v: %v", eof, rerr)
+	}
+	value, rerr := rd.VarOpaque()
+	if rerr != nil || string(value) != "hello" {
+		t.Fatalf("value %q: %v", value, rerr)
+	}
+
+	// The value is visible through the xattr half of the same object.
+	fh := mustLookup(t, h, "a.txt")
+	got, gerr := h.FS.(nfsfs.XattrFS).GetXattr(fh, "user.comment", 0)
+	if gerr != nil || string(got) != "hello" {
+		t.Fatalf("xattr view %q: %v", got, gerr)
+	}
+
+	// REMOVE deletes the attribute.
+	seq++
+	res, _ = run(seq, [][]byte{
+		nfs4.AppendPutfh(nil, dirHandle),
+		nfs4.AppendRemoveArgs(nil, "user.comment"),
+	})
+	wantStatus(t, "nattr remove", res.Status, nfs4.ErrOK)
+	seq++
+	res, _ = run(seq, [][]byte{
+		nfs4.AppendPutfh(nil, dirHandle),
+		nfs4.AppendLookup(nil, "user.comment"),
+	})
+	wantStatus(t, "nattr lookup gone", res.Status, nfs4.ErrNoEnt)
+}
+
+// xdrDecoder decodes the file handle out of a GETFH result body.
+func xdrDecoder(body []byte) ([]byte, error) {
+	return xdr.NewDecoder(body).VarOpaque()
+}