kompose/vendor/golang.org/x/sys/unix/sockcmsg_unix.go
Shubham Minglani 7e378cd546 implement expose service, add tests, fix #140
Implements a kompose specific docker compose label "kompose.service.expose" which can be used to expose the specified services externally. The accepted values are of type string.
If the value is set to "true", the provider sets the endpoint automatically, and for any other value, the value is set as the hostname. If multiple ports are defined in a service, the first one is chosen to be the exposed.

Unit tests, functional tests, glide updates and docs have also been added in this commit for the related feature.
2016-12-21 20:00:38 +05:30

104 lines
2.9 KiB
Go

// Copyright 2011 The Go Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.
// +build darwin dragonfly freebsd linux netbsd openbsd solaris
// Socket control messages
package unix
import "unsafe"
// Round the length of a raw sockaddr up to align it properly.
func cmsgAlignOf(salen int) int {
salign := sizeofPtr
// NOTE: It seems like 64-bit Darwin and DragonFly BSD kernels
// still require 32-bit aligned access to network subsystem.
if darwin64Bit || dragonfly64Bit {
salign = 4
}
return (salen + salign - 1) & ^(salign - 1)
}
// CmsgLen returns the value to store in the Len field of the Cmsghdr
// structure, taking into account any necessary alignment.
func CmsgLen(datalen int) int {
return cmsgAlignOf(SizeofCmsghdr) + datalen
}
// CmsgSpace returns the number of bytes an ancillary element with
// payload of the passed data length occupies.
func CmsgSpace(datalen int) int {
return cmsgAlignOf(SizeofCmsghdr) + cmsgAlignOf(datalen)
}
func cmsgData(h *Cmsghdr) unsafe.Pointer {
return unsafe.Pointer(uintptr(unsafe.Pointer(h)) + uintptr(cmsgAlignOf(SizeofCmsghdr)))
}
// SocketControlMessage represents a socket control message.
type SocketControlMessage struct {
Header Cmsghdr
Data []byte
}
// ParseSocketControlMessage parses b as an array of socket control
// messages.
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 || int(h.Len) > len(b) {
return nil, nil, EINVAL
}
return h, b[cmsgAlignOf(SizeofCmsghdr):h.Len], nil
}
// UnixRights encodes a set of open file descriptors into a socket
// control message for sending to another process.
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))
data := cmsgData(h)
for _, fd := range fds {
*(*int32)(data) = int32(fd)
data = unsafe.Pointer(uintptr(data) + 4)
}
return b
}
// ParseUnixRights decodes a socket control message that contains an
// integer array of open file descriptors from another process.
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
}