[GHC] #2301: Proper handling of SIGINT/SIGQUIT

[GHC]

#2301: Proper handling of SIGINT/SIGQUIT
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        Reporter:  duncan            |            Owner:
            Type:  bug               |           Status:  new
        Priority:  high              |        Milestone:  7.8.1
       Component:                    |          Version:  6.12.3
  libraries/process                  |         Keywords:
      Resolution:                    |     Architecture:  Unknown/Multiple
Operating System:  POSIX             |       Difficulty:  Unknown
 Type of failure:  Incorrect result  |       Blocked By:
  at runtime                         |  Related Tickets:
       Test Case:                    |  #3994,#5766,#7229,#4274,#3318,#1619
        Blocking:                    |
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Comment (by duncan):

 I have a patch to fix this.

 It adds a new `delegate_ctlc :: Bool` to the `CreateProcess` options
 record for delegating control C handling. If you turn that on, then
 `createProcess` will make the parent process ignore SIGINT until
 `waitForProcess` returns (or `getProcessExitCode` returns non-Nothing).

 Then `waitForProcess` (or `getProcessExitCode`) will throw `UserInterrupt`
 if we were delegating, and the process did exit due to SIGINT. This should
 implement the "WCE" protocol ok.

 It should correctly handle the case of there being multiple concurrent
 processes to which we're delegating (unlike the current
 `system`/`rawSystem` which will end up with the wrong signal handlers
 installed).

--
Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/2301#comment:34>
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