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 (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 sendCommandLineArguments(usock *unixsocket.Usock, args []string) error {
master, slave, err := unixsocket.Socketpair(syscall.SOCK_STREAM)
if err != nil {
return err
}
usock.WriteFD(int(slave.Fd()))
if err != nil {
return err
}
slave.Close()
go func() {
defer master.Close()
argAsBytes := []byte{}
for _, arg := range args[1:] {
argAsBytes = append(argAsBytes, []byte(arg)...)
argAsBytes = append(argAsBytes, byte(0))
}
_, err = master.Write(argAsBytes)
if err != nil {
slog.ErrorString("Could not send arguments across: " +
err.Error() + "\r")
return
}
}()
return nil
}
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 sendExitStatus(usock *unixsocket.Usock, exitStatus string, err error) error {
if err != nil {
return err
}
_, err = usock.WriteMessage(exitStatus)
return err
}
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 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 writeStacktrace(usock *unixsocket.Usock, slaveNode *processtree.SlaveNode, clientFile *os.File) {
// Fake process ID / output / error codes:
// Write a fake pid (step 6)
usock.WriteMessage("0")
// Write the error message to the terminal
clientFile.Write([]byte(slaveNode.Error))
// Write a non-positive exit code to the client
usock.WriteMessage("1")
}
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 sendClientPidAndArgumentsToCommand(commandUsock *unixsocket.Usock, clientPid int, argCount int, argFD int, err error) error {
if err != nil {
return err
}
msg := messages.CreatePidAndArgumentsMessage(clientPid, argCount)
_, err = commandUsock.WriteMessage(msg)
if err != nil {
return err
}
return commandUsock.WriteFD(argFD)
}
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, argCount, argFD, 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 != "" {
writeStacktrace(usock, slaveNode, clientFile)
return
}
commandUsock, err := bootNewCommand(slaveNode, command, err)
if err != nil {
// If a client connects while the command is just
// booting up, it actually makes it here - still
// expects a backtrace, of course.
writeStacktrace(usock, slaveNode, clientFile)
return
}
defer commandUsock.Close()
err = sendClientPidAndArgumentsToCommand(commandUsock, clientPid, argCount, argFD, 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!
}
// 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!
}
// 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!
}