Adding the challenge 0403

0403/os_unix.go

@@ -0,0 +1,34 @@
+//go:build unix
+
+package db0403
+
+import (
+	"os"
+	"path"
+	"syscall"
+)
+
+// open or create a file and fsync the directory
+func createFileSync(file string) (*os.File, error) {
+	fp, err := os.OpenFile(file, os.O_RDWR|os.O_CREATE, 0o644)
+	if err != nil {
+		return nil, err
+	}
+	if err = syncDir(path.Base(file)); err != nil {
+		_ = fp.Close()
+		return nil, err
+	}
+	return fp, err
+}
+
+func syncDir(file string) error {
+	flags := os.O_RDONLY | syscall.O_DIRECTORY
+	dirfd, err := syscall.Open(path.Dir(file), flags, 0o644)
+	if err != nil {
+		return err
+	}
+	defer syscall.Close(dirfd)
+	return syscall.Fsync(dirfd)
+}
+
+// QzBQWVJJOUhU https://trialofcode.org/