func receiveExitStatus(commandUsock *unixsocket.Usock, err error) (string, error) {
if err != nil {
return "", err
}
return commandUsock.ReadMessage()
}
func (node *SlaveNode) Run(identifier string, pid int, slaveUsock *unixsocket.Usock) {
// TODO: We actually don't really want to prevent killing this
// process while it's booting up.
node.mu.Lock()
defer node.mu.Unlock()
node.Pid = pid
// The slave will execute its action and respond with a status...
msg, err := slaveUsock.ReadMessage()
if err != nil {
fmt.Println(err)
}
msg, err = ParseActionResponseMessage(msg)
if err != nil {
fmt.Println(err)
}
if msg == "OK" {
node.Socket = slaveUsock.Conn
} else {
node.RegisterError(msg)
}
node.SignalBooted()
slaveBooted(node.Name)
go node.handleMessages()
}
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 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, usock *unixsocket.Usock) {
defer usock.Close()
// we have established first contact to the client.
// we first read the command and arguments specified from the connection. (step 1)
msg, err := usock.ReadMessage()
if err != nil {
fmt.Println(err)
return
}
command, arguments, err := ParseClientCommandRequestMessage(msg)
if err != nil {
fmt.Println(err)
return
}
commandNode := tree.FindCommand(command)
if commandNode == nil {
fmt.Println("ERROR: Node not found!: ", command)
return
}
command = commandNode.Name // resolve aliases
slaveNode := commandNode.Parent
// Now we read the terminal IO socket to use for raw IO (step 2)
clientFd, err := usock.ReadFD()
if err != nil {
fmt.Println("Expected FD, none received!")
return
}
fileName := strconv.Itoa(rand.Int())
clientFile := unixsocket.FdToFile(clientFd, fileName)
defer clientFile.Close()
// We now need to fork a new command process.
// For now, we naively assume it's running...
if 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
}
// boot a command process and establish a socket connection to it.
slaveNode.WaitUntilBooted()
msg = CreateSpawnCommandMessage(command)
slaveNode.mu.Lock()
slaveNode.Socket.Write([]byte(msg))
slaveNode.mu.Unlock()
// TODO: deadline? how to respond if this is never sent?
commandFd := <-slaveNode.ClientCommandPTYFileDescriptor
if err != nil {
fmt.Println("Couldn't start command process!", err)
}
fileName = strconv.Itoa(rand.Int())
commandFile := unixsocket.FdToFile(commandFd, fileName)
defer commandFile.Close()
// Send the arguments to the command process (step 3)
commandFile.Write([]byte(arguments)) // TODO: What if they're too long?
commandSocket, err := unixsocket.MakeUnixSocket(commandFile)
if err != nil {
fmt.Println("MakeUnixSocket", err)
}
defer commandSocket.Close()
// Send the client terminal connection to the command process (step 4)
commandUsock := unixsocket.NewUsock(commandSocket)
commandUsock.WriteFD(clientFd)
// Receive the pid from the command process (step 5)
msg, err = commandUsock.ReadMessage()
if err != nil {
println(err)
}
intPid, _, _ := ParsePidMessage(msg)
// Send the pid to the client process (step 6)
strPid := strconv.Itoa(intPid)
usock.WriteMessage(strPid)
// Receive the exit status from the command (step 7)
msg, err = commandUsock.ReadMessage()
if err != nil {
println(err)
}
// Forward the exit status to the Client (step 8)
usock.WriteMessage(msg)
// Done! Hooray!
}