func StartSlaveMonitor(tree *ProcessTree, local *unixsocket.Usock, remote *os.File, quit chan bool) {
monitor := &SlaveMonitor{tree}
// We just want this unix socket to be a channel so we can select on it...
registeringFds := make(chan int, 3)
go func() {
for {
fd, err := local.ReadFD()
if err != nil {
fmt.Println(err)
}
registeringFds <- fd
}
}()
for _, slave := range monitor.tree.SlavesByName {
if slave.Parent == nil {
go monitor.startInitialProcess(remote)
} else {
go monitor.bootSlave(slave)
}
}
for {
select {
case <-quit:
quit <- true
monitor.cleanupChildren()
return
case fd := <-registeringFds:
monitor.slaveDidBeginRegistration(fd)
}
}
}
func receiveFileFromFD(usock *unixsocket.Usock) (*os.File, error) {
clientFd, err := usock.ReadFD()
if err != nil {
return nil, errors.New("Expected FD, none received!")
}
fileName := strconv.Itoa(rand.Int())
return os.NewFile(uintptr(clientFd), fileName), nil
}
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, int, int, error) {
if err != nil {
return "", -1, -1, -1, err
}
msg, err := usock.ReadMessage()
if err != nil {
return "", -1, -1, -1, err
}
argCount, clientPid, command, err := messages.ParseClientCommandRequestMessage(msg)
if err != nil {
return "", -1, -1, -1, err
}
argFD, err := usock.ReadFD()
return command, clientPid, argCount, argFD, 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!
}