small refactor*

server/pkg/go-nfs/nfs_onwrite.go

@@ -0,0 +1,117 @@
+package nfs
+
+import (
+	"bytes"
+	"context"
+	"errors"
+	"io"
+	"math"
+	"os"
+
+	"github.com/willscott/go-nfs-client/nfs/xdr"
+)
+
+// writeStability is the level of durability requested with the write
+type writeStability uint32
+
+const (
+	unstable writeStability = 0
+	dataSync writeStability = 1
+	fileSync writeStability = 2
+)
+
+type writeArgs struct {
+	Handle []byte
+	Offset uint64
+	Count  uint32
+	How    uint32
+	Data   []byte
+}
+
+func onWrite(ctx context.Context, w *response, userHandle Handler) error {
+	w.errorFmt = wccDataErrorFormatter
+	var req writeArgs
+	if err := xdr.Read(w.req.Body, &req); err != nil {
+		return &NFSStatusError{NFSStatusInval, err}
+	}
+
+	fs, path, err := userHandle.FromHandle(ctx, req.Handle)
+	if err != nil {
+		return &NFSStatusError{NFSStatusStale, err}
+	}
+	// TODO
+	// if !CapabilityCheck(fs, billy.WriteCapability) {
+	// 	return &NFSStatusError{NFSStatusROFS, os.ErrPermission}
+	// }
+	if len(req.Data) > math.MaxInt32 || req.Count > math.MaxInt32 {
+		return &NFSStatusError{NFSStatusFBig, os.ErrInvalid}
+	}
+	if req.How != uint32(unstable) && req.How != uint32(dataSync) && req.How != uint32(fileSync) {
+		return &NFSStatusError{NFSStatusInval, os.ErrInvalid}
+	}
+
+	// stat first for pre-op wcc.
+	fullPath := fs.Join(path...)
+	info, err := fs.Stat(ctx, fullPath)
+	if err != nil {
+		if os.IsNotExist(err) {
+			return &NFSStatusError{NFSStatusNoEnt, err}
+		}
+		if errors.Is(err, context.DeadlineExceeded) {
+			return &NFSStatusError{timeoutStatus, err}
+		}
+		return &NFSStatusError{NFSStatusAccess, err}
+	}
+	if !info.Mode().IsRegular() {
+		return &NFSStatusError{NFSStatusInval, os.ErrInvalid}
+	}
+	preOpCache := ToFileAttribute(info, fullPath).AsCache()
+
+	// now the actual op.
+	file, err := fs.OpenFile(ctx, fs.Join(path...), os.O_RDWR, info.Mode().Perm())
+	if err != nil {
+		return &NFSStatusError{NFSStatusAccess, err}
+	}
+	defer file.Close(ctx)
+	if req.Offset > 0 {
+		if _, err := file.Seek(int64(req.Offset), io.SeekStart); err != nil {
+			return &NFSStatusError{NFSStatusIO, err}
+		}
+	}
+	end := req.Count
+	if len(req.Data) < int(end) {
+		end = uint32(len(req.Data))
+	}
+	writtenCount, err := file.Write(ctx, req.Data[:end])
+	if err != nil {
+		Log.Errorf("Error writing: %v", err)
+		return &NFSStatusError{NFSStatusIO, err}
+	}
+	if err := file.Close(ctx); err != nil {
+		Log.Errorf("error closing: %v", err)
+		return &NFSStatusError{NFSStatusIO, err}
+	}
+
+	writer := bytes.NewBuffer([]byte{})
+	if err := xdr.Write(writer, uint32(NFSStatusOk)); err != nil {
+		return &NFSStatusError{NFSStatusServerFault, err}
+	}
+
+	if err := WriteWcc(writer, preOpCache, tryStat(ctx, fs, path)); err != nil {
+		return &NFSStatusError{NFSStatusServerFault, err}
+	}
+	if err := xdr.Write(writer, uint32(writtenCount)); err != nil {
+		return &NFSStatusError{NFSStatusServerFault, err}
+	}
+	if err := xdr.Write(writer, fileSync); err != nil {
+		return &NFSStatusError{NFSStatusServerFault, err}
+	}
+	if err := xdr.Write(writer, w.Server.ID); err != nil {
+		return &NFSStatusError{NFSStatusServerFault, err}
+	}
+
+	if err := w.Write(writer.Bytes()); err != nil {
+		return &NFSStatusError{NFSStatusServerFault, err}
+	}
+	return nil
+}