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- package unix
- import (
- "unsafe"
- )
- func CmsgLen(datalen int) int {
- return cmsgAlignOf(SizeofCmsghdr) + datalen
- }
- func CmsgSpace(datalen int) int {
- return cmsgAlignOf(SizeofCmsghdr) + cmsgAlignOf(datalen)
- }
- func (h *Cmsghdr) data(offset uintptr) unsafe.Pointer {
- return unsafe.Pointer(uintptr(unsafe.Pointer(h)) + uintptr(cmsgAlignOf(SizeofCmsghdr)) + offset)
- }
- type SocketControlMessage struct {
- Header Cmsghdr
- Data []byte
- }
- func ParseSocketControlMessage(b []byte) ([]SocketControlMessage, error) {
- var msgs []SocketControlMessage
- i := 0
- for i+CmsgLen(0) <= len(b) {
- h, dbuf, err := socketControlMessageHeaderAndData(b[i:])
- if err != nil {
- return nil, err
- }
- m := SocketControlMessage{Header: *h, Data: dbuf}
- msgs = append(msgs, m)
- i += cmsgAlignOf(int(h.Len))
- }
- return msgs, nil
- }
- func socketControlMessageHeaderAndData(b []byte) (*Cmsghdr, []byte, error) {
- h := (*Cmsghdr)(unsafe.Pointer(&b[0]))
- if h.Len < SizeofCmsghdr || uint64(h.Len) > uint64(len(b)) {
- return nil, nil, EINVAL
- }
- return h, b[cmsgAlignOf(SizeofCmsghdr):h.Len], nil
- }
- func UnixRights(fds ...int) []byte {
- datalen := len(fds) * 4
- b := make([]byte, CmsgSpace(datalen))
- h := (*Cmsghdr)(unsafe.Pointer(&b[0]))
- h.Level = SOL_SOCKET
- h.Type = SCM_RIGHTS
- h.SetLen(CmsgLen(datalen))
- for i, fd := range fds {
- *(*int32)(h.data(4 * uintptr(i))) = int32(fd)
- }
- return b
- }
- func ParseUnixRights(m *SocketControlMessage) ([]int, error) {
- if m.Header.Level != SOL_SOCKET {
- return nil, EINVAL
- }
- if m.Header.Type != SCM_RIGHTS {
- return nil, EINVAL
- }
- fds := make([]int, len(m.Data)>>2)
- for i, j := 0, 0; i < len(m.Data); i += 4 {
- fds[j] = int(*(*int32)(unsafe.Pointer(&m.Data[i])))
- j++
- }
- return fds, nil
- }
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