How to get a PTY.spawn baby exit code?

Question

I am trying to manage an SSH connection to a network device through a PTY module with a code like this:

cmd_line = "ssh [e-mail]"
begin
  PTY.spawn(cmd_line) do |r_f,w_f,pid|
  ...
rescue PTY::ChildExited => cended
  ...
end

All I / O works very well, however I don't know how to get the exit status of a child process.

For example, if the connection is broken or simply disconnected, the spawned process will terminate with an error code, but this code does not seem to be returned in a special variable $?.

Answer 1

TL; DR

Use 1.9.2 and wait while the PTY process correctly sets $?

PTY.spawn(command) do |r,w,pid|
  # ...
  Process.wait(pid)
end

Full story

1.9.2 PTY, PTY pid. (AFAIK). , , - , , (. http://redmine.ruby-lang.org/issues/5253).

:

require 'pty'
require 'test/unit'

class PTYTest < Test::Unit::TestCase
  def setup
    system "true"
    assert_equal 0, $?.exitstatus
  end

  def pty(cmd, &block)
    PTY.spawn(cmd, &block)
    $?.exitstatus
  end

  def test_pty_with_wait_correctly_sets_exit_status_for_master_slave_io
    status = pty("printf 'abc'; exit 8") do |r,w,pid|
      while !r.eof?
        r.getc
      end
      Process.wait(pid)
    end
    assert_equal 8, status
  end

  def test_pty_with_wait_correctly_sets_exit_status_for_basic_commands
    status = pty("true") do |r,w,pid|
      Process.wait(pid)
    end
    assert_equal 0, status

    status = pty("false") do |r,w,pid|
      Process.wait(pid)
    end
    assert_equal 1, status
  end

  def test_pty_with_wait_sets_exit_status_1_for_immediate_exit
    status = pty("exit 8") do |r,w,pid|
      Process.wait(pid)
    end
    assert_equal 1, status
  end

  def test_pty_with_kill
    status = pty("sleep 10") do |r,w,pid|
      Process.kill(9, pid)
      Process.wait(pid)
    end

    assert_equal nil, status
  end
end

:

$ ruby -v
ruby 1.9.2p290 (2011-07-09 revision 32553) [x86_64-darwin10.8.0]
$ ruby example.rb
Loaded suite example
Started
....
Finished in 1.093349 seconds.

4 tests, 9 assertions, 0 failures, 0 errors, 0 skips

Test run options: --seed 31924

1.8.7 . rubies PTY PTY:: ChildExited, PTY. , , :

$ ruby -v
ruby 1.8.7 (2010-08-16 patchlevel 302) [i686-darwin10.4.0]
$ ruby example.rb
Loaded suite example
Started
EE.E
Finished in 1.170357 seconds.

  1) Error:
test_pty_with_kill(PTYTest):
PTY::ChildExited: pty - exited: 35196
    example.rb:11:in `test_pty_with_kill'
    example.rb:11:in `spawn'
    example.rb:11:in `pty'
    example.rb:45:in `test_pty_with_kill'

  2) Error:
test_pty_with_wait_correctly_sets_exit_status_for_basic_commands(PTYTest):
PTY::ChildExited: pty - exited: 35198
    example.rb:11:in `test_pty_with_wait_correctly_sets_exit_status_for_basic_commands'
    example.rb:11:in `spawn'
    example.rb:11:in `pty'
    example.rb:26:in `test_pty_with_wait_correctly_sets_exit_status_for_basic_commands'

  3) Error:
test_pty_with_wait_sets_exit_status_1_for_immediate_exit(PTYTest):
PTY::ChildExited: pty - exited: 35202
    example.rb:11:in `test_pty_with_wait_sets_exit_status_1_for_immediate_exit'
    example.rb:11:in `spawn'
    example.rb:11:in `pty'
    example.rb:38:in `test_pty_with_wait_sets_exit_status_1_for_immediate_exit'

4 tests, 5 assertions, 0 failures, 3 errors

, ChildExited, (, , PTY) , . , , , 1.9.2.

. ChildExited, - :

def pty(cmd, &block)
  begin
    PTY.spawn(cmd, &block)
    $?.exitstatus
  rescue PTY::ChildExited
    $!.status.exitstatus
  end
end

, , , 1.9.2, , $? ( 1.9.2). , :

def test_setting_of_process_status
  system "true"
  assert_equal 0, $?.exitstatus

  begin
    PTY.spawn("false") do |r,w,pid|
      Process.wait(pid)
    end
  rescue PTY::ChildExited
  end
  assert_equal 1, $?.exitstatus
end

1.9.2, 1.8.7. 1.8.7 PTY ChildExited - Process.wait , , $?. $? "" true "" , 0 1 .

$? , (.. PTY Process.wait).

Answer 2

, :

• ruby ​​ 1.9.2 PTY.check()

• script

, ruby, , $? script. .

, - script, ...

1.7.7/1.9.1 Ruby

Answer 3

: Linux () s , .
C :

int status,
wait (& status)//
WEXITSTATUS (status)//macro

. ruby, . :)