Add NFSPROC3_Symlink to create symlinks

nfs/file.go

@@ -7,6 +7,7 @@ import (
 	"errors"
 	"io"
 	"os"
+	"path/filepath"
 
 	"github.com/vmware/go-nfs-client/nfs/rpc"
 	"github.com/vmware/go-nfs-client/nfs/util"
@@ -26,6 +27,47 @@ type File struct {
 	fh []byte
 }
 
+// Readlink gets the target of a symlink
+func (f *File) Readlink() (string, error) {
+	type ReadlinkArgs struct {
+		rpc.Header
+		FH []byte
+	}
+
+	type ReadlinkRes struct {
+		Attr PostOpAttr
+		data []byte
+	}
+
+	r, err := f.call(&ReadlinkArgs{
+		Header: rpc.Header{
+			Rpcvers: 2,
+			Prog:    Nfs3Prog,
+			Vers:    Nfs3Vers,
+			Proc:    NFSProc3Readlink,
+			Cred:    f.auth,
+			Verf:    rpc.AuthNull,
+		},
+		FH: f.fh,
+	})
+
+	if err != nil {
+		util.Debugf("readlink(%x): %s", f.fh, err.Error())
+		return "", err
+	}
+
+	readlinkres := &ReadlinkRes{}
+	if err = xdr.Read(r, readlinkres); err != nil {
+		return "", err
+	}
+
+	if readlinkres.data, err = xdr.ReadOpaque(r); err != nil {
+		return "", err
+	}
+
+	return string(readlinkres.data), err
+}
+
 func (f *File) Read(p []byte) (int, error) {
 	type ReadArgs struct {
 		rpc.Header
@@ -245,6 +287,75 @@ func (v *Target) Open(path string) (*File, error) {
 	return f, nil
 }
 
+// Symlink creates a symlink as where pointing to symlink
+func (v *Target) Symlink(where, symlink string) (*File, error) {
+	type symlinkdata3 struct {
+		SymlinkAttr Sattr3
+		SymlinkData []byte
+	}
+
+	type SymlinkArgs struct {
+		rpc.Header
+		Where   Diropargs3
+		Symlink symlinkdata3
+	}
+
+	type SymlinkRes struct {
+		obj     PostOpFH3
+		objAttr PostOpAttr
+		Wcc     WccData
+	}
+
+	symlinkName := filepath.Base(where)
+	symlinkDir := filepath.Dir(where)
+
+	_, fh, err := v.Lookup(symlinkDir)
+	if err != nil {
+		return nil, err
+	}
+
+	r, err := v.call(&SymlinkArgs{
+		Header: rpc.Header{
+			Rpcvers: 2,
+			Prog:    Nfs3Prog,
+			Vers:    Nfs3Vers,
+			Proc:    NFSProc3Symlink,
+			Cred:    v.auth,
+			Verf:    rpc.AuthNull,
+		},
+		Where: Diropargs3{
+			FH:       fh,
+			Filename: symlinkName,
+		},
+		Symlink: symlinkdata3{
+			SymlinkAttr: Sattr3{},
+			SymlinkData: []byte(symlink),
+		},
+	})
+
+	if err != nil {
+		util.Debugf("Symlink(%s): %s", where, err.Error())
+		return nil, err
+	}
+
+	symlinkres := &SymlinkRes{}
+	if err = xdr.Read(r, symlinkres); err != nil {
+		return nil, err
+	}
+
+	if !symlinkres.obj.IsSet {
+		return nil, errors.New("fh not set")
+	}
+
+	symFile := &File{
+		Target: v,
+		fsinfo: v.fsinfo,
+		fh:     symlinkres.obj.FH,
+	}
+
+	return symFile, nil
+}
+
 func min(x, y uint32) uint32 {
 	if x > y {
 		return y

nfs/nfs.go

@@ -22,10 +22,12 @@ const (
 
 	// program methods
 	NFSProc3Lookup      = 3
+	NFSProc3Readlink    = 5
 	NFSProc3Read        = 6
 	NFSProc3Write       = 7
 	NFSProc3Create      = 8
 	NFSProc3Mkdir       = 9
+	NFSProc3Symlink     = 10
 	NFSProc3Remove      = 12
 	NFSProc3RmDir       = 13
 	NFSProc3ReadDirPlus = 17