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//+build !windows,!solaris
package dbus
import (
"bytes"
"encoding/binary"
"errors"
"io"
"net"
"syscall"
)
type oobReader struct {
conn *net.UnixConn
oob []byte
buf [4096]byte
}
func (o *oobReader) Read(b []byte) (n int, err error) {
n, oobn, flags, _, err := o.conn.ReadMsgUnix(b, o.buf[:])
if err != nil {
return n, err
}
if flags&syscall.MSG_CTRUNC != 0 {
return n, errors.New("dbus: control data truncated (too many fds received)")
}
o.oob = append(o.oob, o.buf[:oobn]...)
return n, nil
}
type unixTransport struct {
*net.UnixConn
rdr *oobReader
hasUnixFDs bool
}
func newUnixTransport(keys string) (transport, error) {
var err error
t := new(unixTransport)
abstract := getKey(keys, "abstract")
path := getKey(keys, "path")
switch {
case abstract == "" && path == "":
return nil, errors.New("dbus: invalid address (neither path nor abstract set)")
case abstract != "" && path == "":
t.UnixConn, err = net.DialUnix("unix", nil, &net.UnixAddr{Name: "@" + abstract, Net: "unix"})
if err != nil {
return nil, err
}
return t, nil
case abstract == "" && path != "":
t.UnixConn, err = net.DialUnix("unix", nil, &net.UnixAddr{Name: path, Net: "unix"})
if err != nil {
return nil, err
}
return t, nil
default:
return nil, errors.New("dbus: invalid address (both path and abstract set)")
}
}
func init() {
transports["unix"] = newUnixTransport
}
func (t *unixTransport) EnableUnixFDs() {
t.hasUnixFDs = true
}
func (t *unixTransport) ReadMessage() (*Message, error) {
var (
blen, hlen uint32
csheader [16]byte
headers []header
order binary.ByteOrder
unixfds uint32
)
// To be sure that all bytes of out-of-band data are read, we use a special
// reader that uses ReadUnix on the underlying connection instead of Read
// and gathers the out-of-band data in a buffer.
if t.rdr == nil {
t.rdr = &oobReader{conn: t.UnixConn}
} else {
t.rdr.oob = nil
}
// read the first 16 bytes (the part of the header that has a constant size),
// from which we can figure out the length of the rest of the message
if _, err := io.ReadFull(t.rdr, csheader[:]); err != nil {
return nil, err
}
switch csheader[0] {
case 'l':
order = binary.LittleEndian
case 'B':
order = binary.BigEndian
default:
return nil, InvalidMessageError("invalid byte order")
}
// csheader[4:8] -> length of message body, csheader[12:16] -> length of
// header fields (without alignment)
binary.Read(bytes.NewBuffer(csheader[4:8]), order, &blen)
binary.Read(bytes.NewBuffer(csheader[12:]), order, &hlen)
if hlen%8 != 0 {
hlen += 8 - (hlen % 8)
}
// decode headers and look for unix fds
headerdata := make([]byte, hlen+4)
copy(headerdata, csheader[12:])
if _, err := io.ReadFull(t.rdr, headerdata[4:]); err != nil {
return nil, err
}
dec := newDecoder(bytes.NewBuffer(headerdata), order, make([]int, 0))
dec.pos = 12
vs, err := dec.Decode(Signature{"a(yv)"})
if err != nil {
return nil, err
}
Store(vs, &headers)
for _, v := range headers {
if v.Field == byte(FieldUnixFDs) {
unixfds, _ = v.Variant.value.(uint32)
}
}
all := make([]byte, 16+hlen+blen)
copy(all, csheader[:])
copy(all[16:], headerdata[4:])
if _, err := io.ReadFull(t.rdr, all[16+hlen:]); err != nil {
return nil, err
}
if unixfds != 0 {
if !t.hasUnixFDs {
return nil, errors.New("dbus: got unix fds on unsupported transport")
}
// read the fds from the OOB data
scms, err := syscall.ParseSocketControlMessage(t.rdr.oob)
if err != nil {
return nil, err
}
if len(scms) != 1 {
return nil, errors.New("dbus: received more than one socket control message")
}
fds, err := syscall.ParseUnixRights(&scms[0])
if err != nil {
return nil, err
}
msg, err := DecodeMessageWithFDs(bytes.NewBuffer(all), fds)
if err != nil {
return nil, err
}
// substitute the values in the message body (which are indices for the
// array receiver via OOB) with the actual values
for i, v := range msg.Body {
switch v.(type) {
case UnixFDIndex:
j := v.(UnixFDIndex)
if uint32(j) >= unixfds {
return nil, InvalidMessageError("invalid index for unix fd")
}
msg.Body[i] = UnixFD(fds[j])
case []UnixFDIndex:
idxArray := v.([]UnixFDIndex)
fdArray := make([]UnixFD, len(idxArray))
for k, j := range idxArray {
if uint32(j) >= unixfds {
return nil, InvalidMessageError("invalid index for unix fd")
}
fdArray[k] = UnixFD(fds[j])
}
msg.Body[i] = fdArray
}
}
return msg, nil
}
return DecodeMessage(bytes.NewBuffer(all))
}
func (t *unixTransport) SendMessage(msg *Message) error {
fdcnt, err := msg.CountFds()
if err != nil {
return err
}
if fdcnt != 0 {
if !t.hasUnixFDs {
return errors.New("dbus: unix fd passing not enabled")
}
msg.Headers[FieldUnixFDs] = MakeVariant(uint32(fdcnt))
buf := new(bytes.Buffer)
fds, err := msg.EncodeToWithFDs(buf, nativeEndian)
if err != nil {
return err
}
oob := syscall.UnixRights(fds...)
n, oobn, err := t.UnixConn.WriteMsgUnix(buf.Bytes(), oob, nil)
if err != nil {
return err
}
if n != buf.Len() || oobn != len(oob) {
return io.ErrShortWrite
}
} else {
if err := msg.EncodeTo(t, nativeEndian); err != nil {
return err
}
}
return nil
}
func (t *unixTransport) SupportsUnixFDs() bool {
return true
}
|
