nodefs: port utimens and allocate from fuse/nodefs

nodefs/files_darwin.go

-// Copyright 2019 the Go-FUSE Authors. All rights reserved.
-// Use of this source code is governed by a BSD-style
-// license that can be found in the LICENSE file.
-
-package nodefs
-
-import (
-	"context"
-	"syscall"
-	"time"
-)
-
-func (f *loopbackFile) Allocate(ctx context.Context, off uint64, sz uint64, mode uint32) syscall.Errno {
-	return syscall.ENOSYS
-}
-
-func (f *loopbackFile) Utimens(ctx context.Context, a *time.Time, m *time.Time) syscall.Errno {
-	return syscall.ENOSYS
-}

nodefs/loopback_darwin.go

@@ -8,6 +8,10 @@ import (
 	"context"
 	"syscall"
 	"time"
+	"unsafe"
+
+	"github.com/hanwen/go-fuse/fuse"
+	"github.com/hanwen/go-fuse/internal/utimens"
 )
 
 func (n *loopbackNode) GetXAttr(ctx context.Context, attr string, dest []byte) (uint32, syscall.Errno) {
@@ -30,6 +34,77 @@ func (n *loopbackNode) renameExchange(name string, newparent *loopbackNode, newN
 	return syscall.ENOSYS
 }
 
+func (f *loopbackFile) Allocate(ctx context.Context, off uint64, sz uint64, mode uint32) syscall.Errno {
+	// TODO: Handle `mode` parameter.
+
+	// From `man fcntl` on OSX:
+	//     The F_PREALLOCATE command operates on the following structure:
+	//
+	//             typedef struct fstore {
+	//                 u_int32_t fst_flags;      /* IN: flags word */
+	//                 int       fst_posmode;    /* IN: indicates offset field */
+	//                 off_t     fst_offset;     /* IN: start of the region */
+	//                 off_t     fst_length;     /* IN: size of the region */
+	//                 off_t     fst_bytesalloc; /* OUT: number of bytes allocated */
+	//             } fstore_t;
+	//
+	//     The flags (fst_flags) for the F_PREALLOCATE command are as follows:
+	//
+	//           F_ALLOCATECONTIG   Allocate contiguous space.
+	//
+	//           F_ALLOCATEALL      Allocate all requested space or no space at all.
+	//
+	//     The position modes (fst_posmode) for the F_PREALLOCATE command indicate how to use the offset field.  The modes are as fol-
+	//     lows:
+	//
+	//           F_PEOFPOSMODE   Allocate from the physical end of file.
+	//
+	//           F_VOLPOSMODE    Allocate from the volume offset.
+
+	k := struct {
+		Flags      uint32 // u_int32_t
+		Posmode    int64  // int
+		Offset     int64  // off_t
+		Length     int64  // off_t
+		Bytesalloc int64  // off_t
+	}{
+		0,
+		0,
+		int64(off),
+		int64(sz),
+		0,
+	}
+
+	// Linux version for reference:
+	// err := syscall.Fallocate(int(f.File.Fd()), mode, int64(off), int64(sz))
+	_, _, errno := syscall.Syscall(syscall.SYS_FCNTL, uintptr(f.fd), uintptr(syscall.F_PREALLOCATE), uintptr(unsafe.Pointer(&k)))
+
+	return errno
+}
+
+// timeToTimeval - Convert time.Time to syscall.Timeval
+//
+// Note: This does not use syscall.NsecToTimespec because
+// that does not work properly for times before 1970,
+// see https://github.com/golang/go/issues/12777
+func timeToTimeval(t *time.Time) syscall.Timeval {
+	var tv syscall.Timeval
+	tv.Usec = int32(t.Nanosecond() / 1000)
+	tv.Sec = t.Unix()
+	return tv
+}
+
+// MacOS before High Sierra lacks utimensat() and UTIME_OMIT.
+// We emulate using utimes() and extra GetAttr() calls.
 func (f *loopbackFile) utimens(a *time.Time, m *time.Time) syscall.Errno {
-	return syscall.ENOSYS // XXX
+	var attr fuse.AttrOut
+	if a == nil || m == nil {
+		errno := f.GetAttr(context.Background(), &attr)
+		if errno != 0 {
+			return errno
+		}
+	}
+	tv := utimens.Fill(a, m, &attr.Attr)
+	err := syscall.Futimes(int(f.fd), tv)
+	return ToErrno(err)
 }