utils.go platform imp

utils.go

@@ -17,12 +17,10 @@ import (
 	"path"
 	"path/filepath"
 	"strings"
-	"syscall"
 	"time"
 
 	errw "github.com/pkg/errors"
 	"github.com/ulikunitz/xz"
-	"golang.org/x/sys/unix"
 	"google.golang.org/protobuf/types/known/structpb"
 )
 
@@ -71,13 +69,8 @@ func InitPaths() error {
 			}
 			return errw.Wrapf(err, "checking directory %s", p)
 		}
-		stat, ok := info.Sys().(*syscall.Stat_t)
-		if !ok {
-			// should be impossible on Linux
-			return errw.New("cannot convert to syscall.Stat_t")
-		}
-		if uid != int(stat.Uid) {
-			return errw.Errorf("%s is owned by UID %d but the current UID is %d", p, stat.Uid, uid)
+		if err := checkPathOwner(uid, info); err != nil {
+			return err
 		}
 		if !info.IsDir() {
 			return errw.Errorf("%s should be a directory, but is not", p)
@@ -283,18 +276,6 @@ func ForceSymlink(orig, symlink string) error {
 	return SyncFS(symlink)
 }
 
-func SyncFS(syncPath string) (errRet error) {
-	file, errRet := os.Open(filepath.Dir(syncPath))
-	if errRet != nil {
-		return errw.Wrapf(errRet, "syncing fs %s", syncPath)
-	}
-	_, _, err := unix.Syscall(unix.SYS_SYNCFS, file.Fd(), 0, 0)
-	if err != 0 {
-		errRet = errw.Wrapf(err, "syncing fs %s", syncPath)
-	}
-	return errors.Join(errRet, file.Close())
-}
-
 func WriteFileIfNew(outPath string, data []byte) (bool, error) {
 	//nolint:gosec
 	curFileBytes, err := os.ReadFile(outPath)

utils_linux.go

@@ -0,0 +1,37 @@
+package agent
+
+import (
+	"errors"
+	"io/fs"
+	"os"
+	"path/filepath"
+	"syscall"
+
+	errw "github.com/pkg/errors"
+	"golang.org/x/sys/unix"
+)
+
+// platform-specific UID check.
+func checkPathOwner(uid int, info fs.FileInfo) error {
+	stat, ok := info.Sys().(*syscall.Stat_t)
+	if !ok {
+		// should be impossible on Linux
+		return errw.New("cannot convert to syscall.Stat_t")
+	}
+	if uid != int(stat.Uid) {
+		return errw.Errorf("%s is owned by UID %d but the current UID is %d", info.Name(), stat.Uid, uid)
+	}
+	return nil
+}
+
+func SyncFS(syncPath string) (errRet error) {
+	file, errRet := os.Open(filepath.Dir(syncPath))
+	if errRet != nil {
+		return errw.Wrapf(errRet, "syncing fs %s", syncPath)
+	}
+	_, _, err := unix.Syscall(unix.SYS_SYNCFS, file.Fd(), 0, 0)
+	if err != 0 {
+		errRet = errw.Wrapf(err, "syncing fs %s", syncPath)
+	}
+	return errors.Join(errRet, file.Close())
+}

utils_windows.go

@@ -0,0 +1,25 @@
+package agent
+
+import (
+	"io/fs"
+	"syscall"
+)
+
+// platform-specific UID check.
+func checkPathOwner(uid int, info fs.FileInfo) error {
+	// todo: figure this out on windows.
+	return nil
+}
+
+func SyncFS(syncPath string) error {
+	handle, err := syscall.Open(syncPath, syscall.O_RDWR, 0)
+	if err != nil {
+		return err
+	}
+	defer syscall.CloseHandle(handle)
+	err = syscall.Fsync(handle)
+	if err != nil {
+		return err
+	}
+	return nil
+}