Class: OsCtld::Console::TTY

Inherits:
Object
  • Object
show all
Includes:
OsCtl::Lib::Utils::Log, OsCtl::Lib::Utils::System, Utils::SwitchUser
Defined in:
lib/osctld/console/tty.rb

Overview

Represents a container's tty.

Each tty has its own thread that passes data between the tty and connected clients. Clients can be connected even if the tty is not available, i.e. the container can be stopped.

Direct Known Subclasses

Console

Instance Attribute Summary collapse

Instance Method Summary collapse

Methods included from Utils::SwitchUser

#ct_attach, #ct_control, #ct_exec, #ct_runscript, #ct_syscmd, #init_script, #unlink_file

Constructor Details

#initialize(ct, n) ⇒ TTY

Returns a new instance of TTY



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# File 'lib/osctld/console/tty.rb', line 21

def initialize(ct, n)
  @ct = ct
  @n = n
  @mutex = Mutex.new
  @clients = []
  @wake_r, @wake_w = IO.pipe
  @opened = false
end

Instance Attribute Details

#ctObject (readonly)

Returns the value of attribute ct



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# File 'lib/osctld/console/tty.rb', line 19

def ct
  @ct
end

#nObject (readonly)

Returns the value of attribute n



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# File 'lib/osctld/console/tty.rb', line 19

def n
  @n
end

#tty_in_ioObject (protected)

Returns the value of attribute tty_in_io



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# File 'lib/osctld/console/tty.rb', line 186

def tty_in_io
  @tty_in_io
end

#tty_out_ioObject (protected)

Returns the value of attribute tty_out_io



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# File 'lib/osctld/console/tty.rb', line 186

def tty_out_io
  @tty_out_io
end

#tty_pidObject (protected)

Returns the value of attribute tty_pid



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# File 'lib/osctld/console/tty.rb', line 186

def tty_pid
  @tty_pid
end

Instance Method Details

#add_client(socket) ⇒ Object



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# File 'lib/osctld/console/tty.rb', line 165

def add_client(socket)
  log(:info, ct, "Connecting client to TTY #{n}")

  sync do
    @clients << socket

    if opened?
      wake
    elsif ct.state == :running
      open
      wake
    end
  end
end

#client_read(io) ⇒ Object (protected)



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# File 'lib/osctld/console/tty.rb', line 226

def client_read(io)
  io.read_nonblock(4096)

rescue IOError, Errno::ECONNRESET
  remove_client(io)
  nil
end

#closeObject



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# File 'lib/osctld/console/tty.rb', line 180

def close
  wake(:stop)
  @thread.join if @thread
end

#on_closeObject (protected)



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# File 'lib/osctld/console/tty.rb', line 239

def on_close

end

#openObject



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# File 'lib/osctld/console/tty.rb', line 81

def open
  sync { @opened = true }

  log(:info, ct, "Opening TTY #{n}")

  in_r, in_w = IO.pipe
  out_r, out_w = IO.pipe

  pid = Process.fork do
    STDIN.reopen(in_r)
    STDOUT.reopen(out_w)
    STDERR.reopen(out_w)

    in_w.close
    out_r.close

    @wake_r.close
    @wake_w.close

    SwitchUser.switch_to(
      ct.user.sysusername,
      ct.user.ugid,
      ct.user.homedir,
      ct.cgroup_path
    )

    lxc_ct = LXC::Container.new(ct.id, ct.lxc_home)
    fd = lxc_ct.console_fd(n)
    rows, cols = fd.winsize

    buf = ''

    begin
      loop do
        rs, = IO.select([STDIN, fd])

        rs.each do |io|
          case io
          when STDIN
            buf << STDIN.read_nonblock(4096)

            while i = buf.index("\n")
              cmd = JSON.parse(buf[0..i], symbolize_names: true)

              if cmd[:keys]
                fd.write(Base64.strict_decode64(cmd[:keys]))
                fd.flush
              end

              if cmd[:rows] && cmd[:cols]
                new_rows = cmd[:rows].to_i
                new_cols = cmd[:cols].to_i

                if new_rows > 0 && new_cols > 0 \
                  && (new_rows != rows || new_cols != cols)
                  fd.winsize = [cmd[:rows], cmd[:cols]]
                end
              end

              buf = buf[i+1..-1]
            end

          when fd
            STDOUT.write(fd.read_nonblock(4096))
            STDOUT.flush
          end
        end
      end

    rescue IOError
      exit
    end
  end

  in_r.close
  out_w.close

  sync do
    self.tty_pid = pid
    self.tty_in_io = in_w
    self.tty_out_io = out_r
  end
end

#opened?Boolean (protected)

Returns:

  • (Boolean)


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# File 'lib/osctld/console/tty.rb', line 188

def opened?
  @opened
end

#remove_client(io) ⇒ Object (protected)



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# File 'lib/osctld/console/tty.rb', line 234

def remove_client(io)
  log(:info, ct, "Disconnecting client from TTY #{n}")
  sync { @clients.delete(io) }
end

#startObject



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# File 'lib/osctld/console/tty.rb', line 30

def start
  @thread = Thread.new do
    pid = nil

    catch(:stop) do
      loop do
        clients, select_rs = watch_ios

        rs, = IO.select(select_rs)

        rs.each do |io|
          if clients.include?(io)
            data = client_read(io)
            next if data.nil? || tty_in_io.nil?

            tty_write(tty_in_io, data)

          elsif io == tty_out_io
            data = tty_read(tty_out_io)
            next if data.nil?

            clients.each do |c|
              begin
                c.write(data)
                c.flush

              rescue SystemCallError
                remove_client(c)
              end
            end

          elsif io == @wake_r
            reason = @wake_r.readline.strip
            throw(:stop) if reason == 'stop'
            next
          end
        end
      end
    end

    sync { @clients.each { |c| c.close } }

    # TODO: why is this happening?
    begin
      Process.wait(tty_pid) if tty_pid
    rescue Errno::ECHILD => e
      log(:warn, ct, "Error occurred when closing tty0: #{e.message}")
    end
  end
end

#syncObject (protected)



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# File 'lib/osctld/console/tty.rb', line 243

def sync
  if @mutex.owned?
    yield
  else
    @mutex.synchronize { yield }
  end
end

#tty_read(io) ⇒ Object (protected)



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# File 'lib/osctld/console/tty.rb', line 204

def tty_read(io)
  io.read_nonblock(4096)

rescue IOError
  log(:info, ct, "Closing TTY #{n}")

  sync do
    @opened = false
    self.tty_pid = nil
    self.tty_in_io = nil
    self.tty_out_io = nil
  end

  on_close
  nil
end

#tty_write(io, data) ⇒ Object (protected)



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# File 'lib/osctld/console/tty.rb', line 221

def tty_write(io, data)
  io.write(data)
  io.flush
end

#wake(reason = '') ⇒ Object (protected)



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# File 'lib/osctld/console/tty.rb', line 192

def wake(reason = '')
  @wake_w.puts(reason.to_s)
end

#watch_iosObject (protected)



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# File 'lib/osctld/console/tty.rb', line 196

def watch_ios
  clients = sync { @clients.clone }

  ret = clients + [@wake_r]
  ret << tty_out_io if tty_out_io
  [clients, ret]
end