Merge pull request #92 from willscott/feat/mknod

Implement interface for FS implementations for mknod and link
willscott · Nov 15, 2023 · a91b8b3 · a91b8b3
2 parents e45deb3 + 3c09dcd
commit a91b8b3
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Showing 4 changed files with 267 additions and 5 deletions.
diff --git a/example/osnfs/changeos_unix.go b/example/osnfs/changeos_unix.go
@@ -0,0 +1,29 @@
+//go:build darwin || dragonfly || freebsd || linux || nacl || netbsd || openbsd || solaris
+// +build darwin dragonfly freebsd linux nacl netbsd openbsd solaris
+
+package main
+
+import (
+	"golang.org/x/sys/unix"
+)
+
+func (fs COS) Mknod(path string, mode uint32, major uint32, minor uint32) error {
+	dev := unix.Mkdev(major, minor)
+	return unix.Mknod(fs.Join(fs.Root(), path), mode, int(dev))
+}
+
+func (fs COS) Mkfifo(path string, mode uint32) error {
+	return unix.Mkfifo(fs.Join(fs.Root(), path), mode)
+}
+
+func (fs COS) Link(path string, link string) error {
+	return unix.Link(fs.Join(fs.Root(), path), link)
+}
+
+func (fs COS) Socket(path string) error {
+	fd, err := unix.Socket(unix.AF_UNIX, unix.SOCK_STREAM, 0)
+	if err != nil {
+		return err
+	}
+	return unix.Bind(fd, &unix.SockaddrUnix{Name: fs.Join(fs.Root(), path)})
+}
diff --git a/handler.go b/handler.go
@@ -15,6 +15,7 @@ type Handler interface {
 	Mount(context.Context, net.Conn, MountRequest) (MountStatus, billy.Filesystem, []AuthFlavor)
 
 	// Change can return 'nil' if filesystem is read-only
+	// If the returned value can be cast to `UnixChange`, mknod and link RPCs will be available.
 	Change(billy.Filesystem) billy.Change
 
 	// Optional methods - generic helpers or trivial implementations can be sufficient depending on use case.
@@ -30,6 +31,15 @@ type Handler interface {
 	HandleLimit() int
 }
 
+// UnixChange extends the billy `Change` interface with support for special files.
+type UnixChange interface {
+	billy.Change
+	Mknod(path string, mode uint32, major uint32, minor uint32) error
+	Mkfifo(path string, mode uint32) error
+	Socket(path string) error
+	Link(path string, link string) error
+}
+
 // CachingHandler represents the optional caching work that a user may wish to over-ride with
 // their own implementations, but which can be otherwise provided through defaults.
 type CachingHandler interface {

diff --git a/nfs_onlink.go b/nfs_onlink.go
@@ -1,14 +1,94 @@
 package nfs
 
 import (
+	"bytes"
 	"context"
 	"os"
-)
 
-var linkErrorBody = [12]byte{}
+	"github.com/go-git/go-billy/v5"
+	"github.com/willscott/go-nfs-client/nfs/xdr"
+)
 
 // Backing billy.FS doesn't support hard links
 func onLink(ctx context.Context, w *response, userHandle Handler) error {
-	w.errorFmt = errFormatterWithBody(linkErrorBody[:])
-	return &NFSStatusError{NFSStatusNotSupp, os.ErrPermission}
+	w.errorFmt = wccDataErrorFormatter
+	obj := DirOpArg{}
+	err := xdr.Read(w.req.Body, &obj)
+	if err != nil {
+		return &NFSStatusError{NFSStatusInval, err}
+	}
+	attrs, err := ReadSetFileAttributes(w.req.Body)
+	if err != nil {
+		return &NFSStatusError{NFSStatusInval, err}
+	}
+
+	target, err := xdr.ReadOpaque(w.req.Body)
+	if err != nil {
+		return &NFSStatusError{NFSStatusInval, err}
+	}
+
+	fs, path, err := userHandle.FromHandle(obj.Handle)
+	if err != nil {
+		return &NFSStatusError{NFSStatusStale, err}
+	}
+	if !billy.CapabilityCheck(fs, billy.WriteCapability) {
+		return &NFSStatusError{NFSStatusROFS, os.ErrPermission}
+	}
+
+	if len(string(obj.Filename)) > PathNameMax {
+		return &NFSStatusError{NFSStatusNameTooLong, os.ErrInvalid}
+	}
+
+	newFilePath := fs.Join(append(path, string(obj.Filename))...)
+	if _, err := fs.Stat(newFilePath); err == nil {
+		return &NFSStatusError{NFSStatusExist, os.ErrExist}
+	}
+	if s, err := fs.Stat(fs.Join(path...)); err != nil {
+		return &NFSStatusError{NFSStatusAccess, err}
+	} else if !s.IsDir() {
+		return &NFSStatusError{NFSStatusNotDir, nil}
+	}
+
+	fp := userHandle.ToHandle(fs, append(path, string(obj.Filename)))
+	changer := userHandle.Change(fs)
+	if changer == nil {
+		return &NFSStatusError{NFSStatusAccess, err}
+	}
+	cos, ok := changer.(UnixChange)
+	if !ok {
+		return &NFSStatusError{NFSStatusAccess, err}
+	}
+
+	err = cos.Link(string(target), newFilePath)
+	if err != nil {
+		return &NFSStatusError{NFSStatusAccess, err}
+	}
+	if err := attrs.Apply(changer, fs, newFilePath); err != nil {
+		return &NFSStatusError{NFSStatusIO, err}
+	}
+
+	writer := bytes.NewBuffer([]byte{})
+	if err := xdr.Write(writer, uint32(NFSStatusOk)); err != nil {
+		return &NFSStatusError{NFSStatusServerFault, err}
+	}
+
+	// "handle follows"
+	if err := xdr.Write(writer, uint32(1)); err != nil {
+		return &NFSStatusError{NFSStatusServerFault, err}
+	}
+	if err := xdr.Write(writer, fp); err != nil {
+		return &NFSStatusError{NFSStatusServerFault, err}
+	}
+	if err := WritePostOpAttrs(writer, tryStat(fs, append(path, string(obj.Filename)))); err != nil {
+		return &NFSStatusError{NFSStatusServerFault, err}
+	}
+
+	if err := WriteWcc(writer, nil, tryStat(fs, path)); err != nil {
+		return &NFSStatusError{NFSStatusServerFault, err}
+	}
+
+	if err := w.Write(writer.Bytes()); err != nil {
+		return &NFSStatusError{NFSStatusServerFault, err}
+	}
+	return nil
 }
diff --git a/nfs_onmknod.go b/nfs_onmknod.go
@@ -1,13 +1,156 @@
 package nfs
 
 import (
+	"bytes"
 	"context"
 	"os"
+
+	"github.com/go-git/go-billy/v5"
+	"github.com/willscott/go-nfs-client/nfs/xdr"
+)
+
+type nfs_ftype int32
+
+const (
+	FTYPE_NF3REG  nfs_ftype = 1
+	FTYPE_NF3DIR  nfs_ftype = 2
+	FTYPE_NF3BLK  nfs_ftype = 3
+	FTYPE_NF3CHR  nfs_ftype = 4
+	FTYPE_NF3LNK  nfs_ftype = 5
+	FTYPE_NF3SOCK nfs_ftype = 6
+	FTYPE_NF3FIFO nfs_ftype = 7
 )
 
 // Backing billy.FS doesn't support creation of
 // char, block, socket, or fifo pipe nodes
 func onMknod(ctx context.Context, w *response, userHandle Handler) error {
 	w.errorFmt = wccDataErrorFormatter
-	return &NFSStatusError{NFSStatusNotSupp, os.ErrPermission}
+	obj := DirOpArg{}
+	err := xdr.Read(w.req.Body, &obj)
+	if err != nil {
+		return &NFSStatusError{NFSStatusInval, err}
+	}
+
+	ftype, err := xdr.ReadUint32(w.req.Body)
+	if err != nil {
+		return &NFSStatusError{NFSStatusInval, err}
+	}
+
+	// see if the filesystem supports mknod
+	fs, path, err := userHandle.FromHandle(obj.Handle)
+	if err != nil {
+		return &NFSStatusError{NFSStatusStale, err}
+	}
+	if !billy.CapabilityCheck(fs, billy.WriteCapability) {
+		return &NFSStatusError{NFSStatusROFS, os.ErrPermission}
+	}
+	c := userHandle.Change(fs)
+	if c == nil {
+		return &NFSStatusError{NFSStatusAccess, os.ErrPermission}
+	}
+	cu, ok := c.(UnixChange)
+	if !ok {
+		return &NFSStatusError{NFSStatusAccess, os.ErrPermission}
+	}
+
+	if len(string(obj.Filename)) > PathNameMax {
+		return &NFSStatusError{NFSStatusNameTooLong, os.ErrInvalid}
+	}
+
+	newFilePath := fs.Join(append(path, string(obj.Filename))...)
+	if _, err := fs.Stat(newFilePath); err == nil {
+		return &NFSStatusError{NFSStatusExist, os.ErrExist}
+	}
+	parent, err := fs.Stat(fs.Join(path...))
+	if err != nil {
+		return &NFSStatusError{NFSStatusAccess, err}
+	} else if !parent.IsDir() {
+		return &NFSStatusError{NFSStatusNotDir, nil}
+	}
+	fp := userHandle.ToHandle(fs, append(path, string(obj.Filename)))
+
+	switch nfs_ftype(ftype) {
+	case FTYPE_NF3CHR:
+	case FTYPE_NF3BLK:
+		// read devicedata3 = {sattr3, specdata3}
+		attrs, err := ReadSetFileAttributes(w.req.Body)
+		if err != nil {
+			return &NFSStatusError{NFSStatusInval, err}
+		}
+		specData1, err := xdr.ReadUint32(w.req.Body)
+		if err != nil {
+			return &NFSStatusError{NFSStatusInval, err}
+		}
+		specData2, err := xdr.ReadUint32(w.req.Body)
+		if err != nil {
+			return &NFSStatusError{NFSStatusInval, err}
+		}
+
+		err = cu.Mknod(newFilePath, uint32(attrs.Mode(parent.Mode())), specData1, specData2)
+		if err != nil {
+			return &NFSStatusError{NFSStatusAccess, err}
+		}
+		if err = attrs.Apply(cu, fs, newFilePath); err != nil {
+			return &NFSStatusError{NFSStatusServerFault, err}
+		}
+
+	case FTYPE_NF3SOCK:
+		// read sattr3
+		attrs, err := ReadSetFileAttributes(w.req.Body)
+		if err != nil {
+			return &NFSStatusError{NFSStatusInval, err}
+		}
+		if err := cu.Socket(newFilePath); err != nil {
+			return &NFSStatusError{NFSStatusAccess, err}
+		}
+		if err = attrs.Apply(cu, fs, newFilePath); err != nil {
+			return &NFSStatusError{NFSStatusServerFault, err}
+		}
+
+	case FTYPE_NF3FIFO:
+		// read sattr3
+		attrs, err := ReadSetFileAttributes(w.req.Body)
+		if err != nil {
+			return &NFSStatusError{NFSStatusInval, err}
+		}
+		err = cu.Mkfifo(newFilePath, uint32(attrs.Mode(parent.Mode())))
+		if err != nil {
+			return &NFSStatusError{NFSStatusAccess, err}
+		}
+		if err = attrs.Apply(cu, fs, newFilePath); err != nil {
+			return &NFSStatusError{NFSStatusServerFault, err}
+		}
+
+	default:
+		return &NFSStatusError{NFSStatusBadType, os.ErrInvalid}
+		// end of input.
+	}
+
+	writer := bytes.NewBuffer([]byte{})
+	if err := xdr.Write(writer, uint32(NFSStatusOk)); err != nil {
+		return &NFSStatusError{NFSStatusServerFault, err}
+	}
+
+	// "handle follows"
+	if err := xdr.Write(writer, uint32(1)); err != nil {
+		return &NFSStatusError{NFSStatusServerFault, err}
+	}
+	// fh3
+	if err := xdr.Write(writer, fp); err != nil {
+		return &NFSStatusError{NFSStatusServerFault, err}
+	}
+	// attr
+	if err := WritePostOpAttrs(writer, tryStat(fs, append(path, string(obj.Filename)))); err != nil {
+		return &NFSStatusError{NFSStatusServerFault, err}
+	}
+	// wcc
+	if err := WriteWcc(writer, nil, tryStat(fs, path)); err != nil {
+		return &NFSStatusError{NFSStatusServerFault, err}
+	}
+
+	if err := w.Write(writer.Bytes()); err != nil {
+		return &NFSStatusError{NFSStatusServerFault, err}
+	}
+
+	return nil
 }