func sendTTYToCommand(commandUsock *unixsocket.Usock, clientFile *os.File, err error) error {
if err != nil {
return err
}
return commandUsock.WriteFD(int(clientFile.Fd()))
}
func receiveExitStatus(commandUsock *unixsocket.Usock, err error) (string, error) {
if err != nil {
return "", err
}
return commandUsock.ReadMessage()
}
func sendExitStatus(usock *unixsocket.Usock, exitStatus string, err error) error {
if err != nil {
return err
}
_, err = usock.WriteMessage(exitStatus)
return err
}
func sendClientPidAndArgumentsToCommand(commandUsock *unixsocket.Usock, clientPid int, arguments string, err error) error {
if err != nil {
return err
}
msg := messages.CreatePidAndArgumentsMessage(clientPid, arguments)
_, err = commandUsock.WriteMessage(msg)
return err
}
func sendCommandPidToClient(usock *unixsocket.Usock, pid int, err error) error {
if err != nil {
return err
}
strPid := strconv.Itoa(pid)
_, err = usock.WriteMessage(strPid)
return err
}
func receivePidFromCommand(commandUsock *unixsocket.Usock, err error) (int, error) {
if err != nil {
return -1, err
}
msg, err := commandUsock.ReadMessage()
if err != nil {
return -1, err
}
intPid, _, _ := messages.ParsePidMessage(msg)
return intPid, err
}
func receiveTTY(usock *unixsocket.Usock, err error) (*os.File, error) {
if err != nil {
return nil, err
}
clientFd, err := usock.ReadFD()
if err != nil {
return nil, errors.New("Expected FD, none received!")
}
fileName := strconv.Itoa(rand.Int())
clientFile := unixsocket.FdToFile(clientFd, fileName)
return clientFile, nil
}
func receiveCommandArgumentsAndPid(usock *unixsocket.Usock, err error) (string, int, string, error) {
if err != nil {
return "", -1, "", err
}
msg, err := usock.ReadMessage()
if err != nil {
return "", -1, "", err
}
command, clientPid, arguments, err := messages.ParseClientCommandRequestMessage(msg)
if err != nil {
return "", -1, "", err
}
return command, clientPid, arguments, err
}
// see docs/client_master_handshake.md
func handleClientConnection(tree *processtree.ProcessTree, usock *unixsocket.Usock) {
defer usock.Close()
// we have established first contact to the client.
command, clientPid, arguments, err := receiveCommandArgumentsAndPid(usock, nil)
commandNode, slaveNode, err := findCommandAndSlaveNodes(tree, command, err)
if err != nil {
// connection was established, no data was sent. Ignore.
return
}
command = commandNode.Name // resolve aliases
clientFile, err := receiveTTY(usock, err)
defer clientFile.Close()
if err == nil && slaveNode.Error != "" {
// we can skip steps 3-5 as they deal with the command process we're not spawning.
// Write a fake pid (step 6)
usock.WriteMessage("0")
// Write the error message to the terminal
clientFile.Write([]byte(slaveNode.Error))
// Skip step 7, and write an exit code to the client (step 8)
usock.WriteMessage("1")
return
}
commandUsock, err := bootNewCommand(slaveNode, command, err)
defer commandUsock.Close()
err = sendClientPidAndArgumentsToCommand(commandUsock, clientPid, arguments, err)
err = sendTTYToCommand(commandUsock, clientFile, err)
cmdPid, err := receivePidFromCommand(commandUsock, err)
err = sendCommandPidToClient(usock, cmdPid, err)
exitStatus, err := receiveExitStatus(commandUsock, err)
err = sendExitStatus(usock, exitStatus, err)
if err != nil {
slog.Error(err)
}
// Done! Hooray!
}