// Unlock unlocks a region of the mapped shared memory
func (buf *sharedBuffer) Unlock(offset, length int) error {
b := buf.Bytes()
err := checkOffsetLength(b, offset, length)
if err == nil {
err = syscall.Munlock(b[offset : offset+length])
}
return os.NewSyscallError("shm: munlock", err)
}
func mmapFile(fileName string) (*mmapData, error) {
file, err := os.Open(fileName)
if err != nil {
return nil, err
}
stat, err := file.Stat()
if err != nil {
file.Close()
return nil, err
}
size := stat.Size()
pageAlignedSize := (size + 4095) &^ 4095
data, err := syscall.Mmap(int(file.Fd()), 0, int(pageAlignedSize),
syscall.PROT_READ, syscall.MAP_PRIVATE)
if err != nil {
file.Close()
return nil, err
}
err = syscall.Mlock(data)
if err != nil {
syscall.Munmap(data)
file.Close()
return nil, err
}
md := &mmapData{file, data[:size]}
runtime.SetFinalizer(md, func(m *mmapData) {
syscall.Munlock(m.d)
syscall.Munmap(m.d)
m.f.Close()
})
return md, nil
}
// Unlock implements Map.Unlock().
func (m *mmap) Unlock() error {
m.RLock()
defer m.RUnlock()
return syscall.Munlock(m.data)
}
// Undo lock.
func (m Mmap) Unlock() error {
return syscall.Munlock(m)
}