Fix several Utimens-related build problems on OSX

Properly implementing Utimens caused the OSX build to break because
the utimensat system call is not available there.

This patch reverts the OSX implementation of Utimens to using
syscall.Utimes(). This is not actually correct but the best we can do.

Thanks to @spaghetti2514 who reported the issue and tested the patches.

fuse/nodefs/files.go

@@ -5,7 +5,6 @@ import (
 	"os"
 	"sync"
 	"syscall"
-	"time"
 
 	"github.com/hanwen/go-fuse/fuse"
 )
@@ -201,30 +200,7 @@ func (f *loopbackFile) GetAttr(a *fuse.Attr) fuse.Status {
 	return fuse.OK
 }
 
-const _UTIME_NOW = ((1 << 30) - 1)
-const _UTIME_OMIT = ((1 << 30) - 2)
-
-// Utimens - file handle based version of loopbackFileSystem.Utimens()
-func (f *loopbackFile) Utimens(a *time.Time, m *time.Time) fuse.Status {
-	var ts [2]syscall.Timespec
-
-	if a == nil {
-		ts[0].Nsec = _UTIME_OMIT
-	} else {
-		ts[0].Sec = a.Unix()
-	}
-
-	if m == nil {
-		ts[1].Nsec = _UTIME_OMIT
-	} else {
-		ts[1].Sec = m.Unix()
-	}
-
-	f.lock.Lock()
-	err := futimens(int(f.File.Fd()), &ts)
-	f.lock.Unlock()
-	return fuse.ToStatus(err)
-}
+// Utimens implemented in files_linux.go
 
 // Allocate implemented in files_linux.go
 

fuse/nodefs/files_darwin.go

@@ -60,3 +60,40 @@ func (f *loopbackFile) Allocate(off uint64, sz uint64, mode uint32) fuse.Status
 	}
 	return fuse.OK
 }
+
+const _UTIME_NOW = ((1 << 30) - 1)
+const _UTIME_OMIT = ((1 << 30) - 2)
+
+// 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
+}
+
+// OSX does not have the utimensat syscall neded to implement this properly.
+// We do our best to emulate it using futimes.
+func (f *loopbackFile) Utimens(a *time.Time, m *time.Time) fuse.Status {
+	tv := make([]syscall.Timeval, 2)
+	if a == nil {
+		tv[0].Usec = _UTIME_OMIT
+	} else {
+		tv[0] = timeToTimeval(a)
+	}
+
+	if m == nil {
+		tv[1].Usec = _UTIME_OMIT
+	} else {
+		tv[1] = timeToTimeval(m)
+	}
+
+	f.lock.Lock()
+	err := syscall.Futimes(int(f.File.Fd()), tv)
+	f.lock.Unlock()
+	return fuse.ToStatus(err)
+}

fuse/nodefs/files_linux.go

@@ -2,6 +2,7 @@ package nodefs
 
 import (
 	"syscall"
+	"time"
 
 	"github.com/hanwen/go-fuse/fuse"
 )
@@ -15,3 +16,28 @@ func (f *loopbackFile) Allocate(off uint64, sz uint64, mode uint32) fuse.Status
 	}
 	return fuse.OK
 }
+
+const _UTIME_NOW = ((1 << 30) - 1)
+const _UTIME_OMIT = ((1 << 30) - 2)
+
+// Utimens - file handle based version of loopbackFileSystem.Utimens()
+func (f *loopbackFile) Utimens(a *time.Time, m *time.Time) fuse.Status {
+	var ts [2]syscall.Timespec
+
+	if a == nil {
+		ts[0].Nsec = _UTIME_OMIT
+	} else {
+		ts[0].Sec = a.Unix()
+	}
+
+	if m == nil {
+		ts[1].Nsec = _UTIME_OMIT
+	} else {
+		ts[1].Sec = m.Unix()
+	}
+
+	f.lock.Lock()
+	err := futimens(int(f.File.Fd()), &ts)
+	f.lock.Unlock()
+	return fuse.ToStatus(err)
+}

fuse/pathfs/loopback.go

@@ -6,7 +6,6 @@ import (
 	"os"
 	"path/filepath"
 	"syscall"
-	"time"
 
 	"github.com/hanwen/go-fuse/fuse"
 	"github.com/hanwen/go-fuse/fuse/nodefs"
@@ -118,29 +117,6 @@ func (fs *loopbackFileSystem) Truncate(path string, offset uint64, context *fuse
 	return fuse.ToStatus(os.Truncate(fs.GetPath(path), int64(offset)))
 }
 
-const _UTIME_NOW = ((1 << 30) - 1)
-const _UTIME_OMIT = ((1 << 30) - 2)
-
-// Utimens - path based version of loopbackFile.Utimens()
-func (fs *loopbackFileSystem) Utimens(path string, a *time.Time, m *time.Time, context *fuse.Context) (code fuse.Status) {
-	var ts [2]syscall.Timespec
-
-	if a == nil {
-		ts[0].Nsec = _UTIME_OMIT
-	} else {
-		ts[0].Sec = a.Unix()
-	}
-
-	if m == nil {
-		ts[1].Nsec = _UTIME_OMIT
-	} else {
-		ts[1].Sec = m.Unix()
-	}
-
-	err := sysUtimensat(0, fs.GetPath(path), &ts, _AT_SYMLINK_NOFOLLOW)
-	return fuse.ToStatus(err)
-}
-
 func (fs *loopbackFileSystem) Readlink(name string, context *fuse.Context) (out string, code fuse.Status) {
 	f, err := os.Readlink(fs.GetPath(name))
 	return f, fuse.ToStatus(err)

fuse/pathfs/loopback_darwin.go

@@ -2,6 +2,7 @@ package pathfs
 
 import (
 	"syscall"
+	"time"
 
 	"github.com/hanwen/go-fuse/fuse"
 )
@@ -21,3 +22,38 @@ func (fs *loopbackFileSystem) StatFs(name string) *fuse.StatfsOut {
 	}
 	return nil
 }
+
+const _UTIME_NOW = ((1 << 30) - 1)
+const _UTIME_OMIT = ((1 << 30) - 2)
+
+// 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
+}
+
+// OSX does not have the utimensat syscall neded to implement this properly.
+// We do our best to emulate it using futimes.
+func (fs *loopbackFileSystem) Utimens(path string, a *time.Time, m *time.Time, context *fuse.Context) fuse.Status {
+	tv := make([]syscall.Timeval, 2)
+	if a == nil {
+		tv[0].Usec = _UTIME_OMIT
+	} else {
+		tv[0] = timeToTimeval(a)
+	}
+
+	if m == nil {
+		tv[1].Usec = _UTIME_OMIT
+	} else {
+		tv[1] = timeToTimeval(m)
+	}
+
+	err := syscall.Utimes(path, tv)
+	return fuse.ToStatus(err)
+}

fuse/pathfs/loopback_linux.go

@@ -3,6 +3,7 @@ package pathfs
 import (
 	"fmt"
 	"syscall"
+	"time"
 
 	"github.com/hanwen/go-fuse/fuse"
 )
@@ -51,3 +52,26 @@ func (fs *loopbackFileSystem) SetXAttr(name string, attr string, data []byte, fl
 	err := syscall.Setxattr(fs.GetPath(name), attr, data, flags)
 	return fuse.ToStatus(err)
 }
+
+const _UTIME_NOW = ((1 << 30) - 1)
+const _UTIME_OMIT = ((1 << 30) - 2)
+
+// Utimens - path based version of loopbackFile.Utimens()
+func (fs *loopbackFileSystem) Utimens(path string, a *time.Time, m *time.Time, context *fuse.Context) (code fuse.Status) {
+	var ts [2]syscall.Timespec
+
+	if a == nil {
+		ts[0].Nsec = _UTIME_OMIT
+	} else {
+		ts[0].Sec = a.Unix()
+	}
+
+	if m == nil {
+		ts[1].Nsec = _UTIME_OMIT
+	} else {
+		ts[1].Sec = m.Unix()
+	}
+
+	err := sysUtimensat(0, fs.GetPath(path), &ts, _AT_SYMLINK_NOFOLLOW)
+	return fuse.ToStatus(err)
+}