Bug #6131: Ctrl-C handler do not work from exec process (Windows)

• Status: Closed
• Assignee: h.shirosaki (Hiroshi Shirosaki)
• Target version: 1.9.3
• ruby -v: ruby 1.9.3-p155 (2012-03-03) [i386-mingw32]

[luislavena (Luis Lavena)]

Hello,

Originally reported to TheCodeShop group: https://groups.google.com/forum/?fromgroups#!topic/thecodeshop/ZI9FY-RKYgs

The usage of "rails server" uses exec to spawn another process to run a server, and that process do not handle Ctrl-C.

Script to recreate this issue:

https://gist.github.com/2009356

=begin a.rb
trap(:INT) do
puts "Hit Ctrl+C in a.rb"
end

exec "ruby b.rb"
=end

=begin b.rb
trap(:INT) do
puts "Hit Ctrl+C in b.rb"
exit(false)
end

sleep
=end

Invoking b directly from command line works, but from a.rb it fails to respond to Ctrl-C

[shyouhei (Shyouhei Urabe)]

• Status changed from Open to Assigned

[phasis68 (Heesob Park)]

As you may know, this bug is due to the Revision r34387.

If the CREATE_NEW_PROCESS_GROUP flag is specified in a call to the CreateProcess function, CTRL+C signal is disabled for all processes within the new process group.

I think r34387 is better to be reverted for compatibility with existing applications.

[usa (Usaku NAKAMURA)]

• Assignee changed from usa (Usaku NAKAMURA) to h.shirosaki (Hiroshi Shirosaki)

r34389 (not 34387) is the revision.

Shirosaki-san, how do you think about this?

[h.shirosaki (Hiroshi Shirosaki)]

How about removing CREATE_NEW_PROCESS_GROUP flag by default and providing a way to specify CREATE_NEW_PROCESS_GROUP flag by spawn methods's arguments?
Ruby user can specify CREATE_NEW_PROCESS_GROUP flag if it's needed.

spawn method has options parameter hash.

spawn(command, options={}) -> Integer
spawn(env, command, options={}) -> Integer
spawn(env, program, *args, options={}) -> Integer

Specify options:
{ :creationflags => Process::CREATE_NEW_PROCESS_GROUP }

Python module does similar things.
http://docs.python.org/library/subprocess.html#subprocess.CREATE_NEW_PROCESS_GROUP

[nobu (Nobuyoshi Nakada)]

h.shirosaki (Hiroshi Shirosaki) wrote:

Specify options:
{ :creationflags => Process::CREATE_NEW_PROCESS_GROUP }

Silly option. Should be 'new_process_group: true' or similar, at least.

Python module does similar things.
http://docs.python.org/library/subprocess.html#subprocess.CREATE_NEW_PROCESS_GROUP

Sigh.

[h.shirosaki (Hiroshi Shirosaki)]

• File process.patch process.patch added

nobu (Nobuyoshi Nakada) wrote:

Should be 'new_process_group: true' or similar, at least.

How about new_pgroup: true? :pgroup option already exists and this is alike pgroup.

I created a patch attached.

• remove CREATE_NEW_PROCESS_GROUP flag by default
• add option new_pgroup: true to specify CREATE_NEW_PROCESS_GROUP flag

Any opinions?

[h.shirosaki (Hiroshi Shirosaki)]

• Assignee changed from h.shirosaki (Hiroshi Shirosaki) to usa (Usaku NAKAMURA)

Assigned to usa-san for comments.

[usa (Usaku NAKAMURA)]

Hello,

In message "[ruby-core:44154] [ruby-trunk - Bug #6131] Ctrl-C handler do not work from exec process (Windows)"
on Apr.06,2012 18:55:27, [e-mail] wrote:

Assigned to usa-san for comments.

Oops, sorry, I overlooked.

I also considered the alternative plan, but I got no idea.
Let it go. Shirosaki-san, please commit it.

Regards,

U.Nakamura [e-mail]

[luislavena (Luis Lavena)]

• Assignee changed from usa (Usaku NAKAMURA) to h.shirosaki (Hiroshi Shirosaki)

Hiroshi: will be good do this in two commits:

• First commit that reverts the usage of CREATE_NEW_PROCESS_GROUP, so can be backported to ruby_1_9_3 branch
• Implement new_pgroup option for spawn.

Thank you.

• Status changed from Assigned to Closed
• % Done changed from 0 to 100

This issue was solved with changeset r35249.
Luis, thank you for reporting this issue.
Your contribution to Ruby is greatly appreciated.
May Ruby be with you.

---

• test/ruby/test_thread.rb
  (TestThreadGroup#test_thread_timer_and_interrupt): skip on Windows.
  Process.kill cannot kill a subprocess if CREATE_NEW_PROCESS_GROUP
  flag is not specified in a call to CreateProcessW().

• win32/win32.c (CreateChild): revert the usage of
  CREATE_NEW_PROCESS_GROUP flag for compatibility.
  [ruby-core:43245][Bug #6131]

[h.shirosaki (Hiroshi Shirosaki)]

Hi Luis,

Hiroshi: will be good do this in two commits:

• First commit that reverts the usage of CREATE_NEW_PROCESS_GROUP, so can be backported to ruby_1_9_3 branch
• Implement new_pgroup option for spawn.

I've committed this in two commits. Please check.