Class: Bolt::Transport::Local::Shell

Inherits:
Sudoable::Connection show all
Defined in:
lib/bolt/transport/local/shell.rb

Constant Summary collapse

CHUNK_SIZE = 
4096

Instance Attribute Summary collapse

Instance Method Summary collapse

Methods inherited from Sudoable::Connection

#make_executable, #make_tempdir, #run_as, #running_as, #with_tempdir, #write_executable

Constructor Details

#initialize(target) ⇒ Shell

Returns a new instance of Shell.



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# File 'lib/bolt/transport/local/shell.rb', line 17

def initialize(target)
  @target = target
  # The familiar problem: Etc.getlogin is broken on osx
  @user = ENV['USER'] || Etc.getlogin
  @run_as = target.options['run-as']
  @logger = Logging.logger[self]
end

Instance Attribute Details

#logger ⇒ Object

Returns the value of attribute logger.



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# File 'lib/bolt/transport/local/shell.rb', line 12

def logger
  @logger
end

#run_as=(value) ⇒ Object (writeonly)

Sets the attribute run_as

Parameters:

  • value —

    the value to set the attribute run_as to.



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# File 'lib/bolt/transport/local/shell.rb', line 13

def run_as=(value)
  @run_as = value
end

#target ⇒ Object

Returns the value of attribute target.



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# File 'lib/bolt/transport/local/shell.rb', line 12

def target
  @target
end

#user ⇒ Object

Returns the value of attribute user.



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# File 'lib/bolt/transport/local/shell.rb', line 12

def user
  @user
end

Instance Method Details

#check_sudo(out, inp, pid) ⇒ Object

See if there’s a sudo prompt in the output If not, return the output



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# File 'lib/bolt/transport/local/shell.rb', line 99

def check_sudo(out, inp, pid)
  buffer = out.readpartial(CHUNK_SIZE)
  # Split on newlines, including the newline
  lines = buffer.split(/(?<=[\n])/)
  # handle_sudo will return the line if it is not a sudo prompt or error
  lines.map! { |line| handle_sudo(inp, line, pid) }
  lines.join("")
# If stream has reached EOF, no password prompt is expected
# return an empty string
rescue EOFError
  ''
end

#copy_file(source, dest) ⇒ Object 



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# File 'lib/bolt/transport/local/shell.rb', line 68

def copy_file(source, dest)
  if source.is_a?(StringIO)
    File.open("tempfile", "w") { |f| f.write(source.read) }
    execute(['mv', 'tempfile', dest])
  else
    # Mimic the behavior of `cp --remove-destination`
    # since the flag isn't supported on MacOS
    result = execute(['rm', '-rf', dest])
    if result.exit_code != 0
      message = "Could not remove existing file #{dest}: #{result.stderr.string}"
      raise Bolt::Node::FileError.new(message, 'REMOVE_ERROR')
    end

    result = execute(['cp', '-r', source, dest])
    if result.exit_code != 0
      message = "Could not copy file to #{dest}: #{result.stderr.string}"
      raise Bolt::Node::FileError.new(message, 'COPY_ERROR')
    end
  end
end

#execute(command, sudoable: true, **options) ⇒ Object 



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# File 'lib/bolt/transport/local/shell.rb', line 112

def execute(command, sudoable: true, **options)
  run_as = options[:run_as] || self.run_as
  escalate = sudoable && run_as && @user != run_as
  use_sudo = escalate && @target.options['run-as-command'].nil?

  if options[:interpreter]
    if command.is_a?(Array)
      command.unshift(options[:interpreter])
    else
      command = [options[:interpreter], command]
    end
  end

  command_str = command.is_a?(String) ? command : Shellwords.shelljoin(command)

  if escalate
    if use_sudo
      sudo_flags = ["sudo", "-k", "-S", "-u", run_as, "-p", Sudoable.sudo_prompt]
      sudo_flags += ["-E"] if options[:environment]
      sudo_str = Shellwords.shelljoin(sudo_flags)
      command_str = "#{sudo_str} #{command_str}"
    else
      run_as_str = Shellwords.shelljoin(@target.options['run-as-command'] + [run_as])
      command_str = "#{run_as_str} #{command_str}"
    end
  end

  command_arr = options[:environment].nil? ? [command_str] : [options[:environment], command_str]

  # Prepare the variables!
  result_output = Bolt::Node::Output.new
  in_buffer = options[:stdin] || ''
  # Chunks of this size will be read in one iteration
  index = 0
  timeout = 0.1

  inp, out, err, t = Open3.popen3(*command_arr)
  read_streams = { out => String.new,
                   err => String.new }
  write_stream = in_buffer.empty? ? [] : [inp]

  # See if there's a sudo prompt
  if use_sudo
    ready_read = select([err], nil, nil, timeout * 5)
    read_streams[err] << check_sudo(err, inp, t.pid) if ready_read
  end

  # True while the process is running or waiting for IO input
  while t.alive?
    # See if we can read from out or err, or write to in
    ready_read, ready_write, = select(read_streams.keys, write_stream, nil, timeout)

    # Read from out and err
    ready_read&.each do |stream|
      begin
        # Check for sudo prompt
        read_streams[stream] << if use_sudo
                                  check_sudo(stream, inp, t.pid)
                                else
                                  stream.readpartial(CHUNK_SIZE)
                                end
      rescue EOFError
      end
    end

    # select will either return an empty array if there are no
    # writable streams or nil if no IO object is available before the
    # timeout is reached.
    writable = if ready_write.respond_to?(:empty?)
                 !ready_write.empty?
               else
                 !ready_write.nil?
               end

    begin
      if writable && index < in_buffer.length
        to_print = in_buffer[index..-1]
        written = inp.write_nonblock to_print
        index += written

        if index >= in_buffer.length && !write_stream.empty?
          inp.close
          write_stream = []
        end
      end
      # If a task has stdin as an input_method but doesn't actually
      # read from stdin, the task may return and close the input stream
    rescue Errno::EPIPE
      write_stream = []
    end
  end
  # Read any remaining data in the pipe. Do not wait for
  # EOF in case the pipe is inherited by a child process.
  read_streams.each do |stream, _|
    begin
      loop { read_streams[stream] << stream.read_nonblock(CHUNK_SIZE) }
    rescue Errno::EAGAIN, EOFError
    end
  end
  result_output.stdout << read_streams[out]
  result_output.stderr << read_streams[err]
  result_output.exit_code = t.value.exitstatus
  result_output
end

#handle_sudo(stdin, err, pid) ⇒ Object

If prompted for sudo password, send password to stdin and return an empty string. Otherwise, check for sudo errors and raise Bolt error. If error is not sudo-related, return the stderr string to be added to node output



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# File 'lib/bolt/transport/local/shell.rb', line 29

def handle_sudo(stdin, err, pid)
  if err.include?(Sudoable.sudo_prompt)
    # A wild sudo prompt has appeared!
    if @target.options['sudo-password']
      # Hopefully no one's sudo-password is > 64kb
      stdin.write("#{@target.options['sudo-password']}\n")
      ''
    else
      raise Bolt::Node::EscalateError.new(
        "Sudo password for user #{@user} was not provided for localhost",
        'NO_PASSWORD'
      )
    end
  else
    handle_sudo_errors(err, pid)
  end
end

#handle_sudo_errors(err, pid) ⇒ Object 



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# File 'lib/bolt/transport/local/shell.rb', line 47

def handle_sudo_errors(err, pid)
  if err =~ /^#{@user} is not in the sudoers file\./
    @logger.debug { err }
    raise Bolt::Node::EscalateError.new(
      "User #{@user} does not have sudo permission on localhost",
      'SUDO_DENIED'
    )
  elsif err =~ /^Sorry, try again\./
    @logger.debug { err }
    # CODEREVIEW can we kill a sudo process without sudo password?
    Process.kill('TERM', pid)
    raise Bolt::Node::EscalateError.new(
      "Sudo password for user #{@user} not recognized on localhost",
      'BAD_PASSWORD'
    )
  else
    # No need to raise an error - just return the string
    err
  end
end

#with_tmpscript(script) ⇒ Object 



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# File 'lib/bolt/transport/local/shell.rb', line 89

def with_tmpscript(script)
  with_tempdir do |dir|
    dest = File.join(dir.to_s, File.basename(script))
    copy_file(script, dest)
    yield dest, dir
  end
end