[GHC] #14262: fdReady cannot wait more than 49 days

[GHC]

#14262: fdReady cannot wait more than 49 days
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        Reporter:  nh2               |                Owner:  (none)
            Type:  bug               |               Status:  new
        Priority:  normal            |            Milestone:
       Component:  Compiler          |              Version:  8.2.1
      Resolution:                    |             Keywords:
Operating System:  Unknown/Multiple  |         Architecture:  x86_64
                                     |  (amd64)
 Type of failure:  None/Unknown      |            Test Case:
      Blocked By:                    |             Blocking:
 Related Tickets:  #8684, #13497,    |  Differential Rev(s):
  #14267                             |
       Wiki Page:                    |
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Comment (by Ben Gamari <ben@…>):

 In [changeset:"f209e6672fe33235bd1d4c20c87894021cf3bbc8/ghc"
 f209e667/ghc]:
 {{{
 #!CommitTicketReference repository="ghc"
 revision="f209e6672fe33235bd1d4c20c87894021cf3bbc8"
 base: fdReady(): Fix timeouts > ~49 days overflowing. Fixes #14262.

 On 64-bit UNIX and Windows, Haskell `Int` has 64 bits
 but C `int msecs` has 32 bits, resulting in an overflow.

 This commit fixes it by switching fdReady() to take int64_t,
 into which a Haskell `Int` will always fit.

 (Note we could not switch to `long long` because that is
 32 bit on 64-bit Windows machines.)

 Further, to be able to actually wait longer than ~49 days,
 we put loops around the waiting syscalls (they all accept only
 32-bit integers).

 Note the timer signal would typically interrupt the syscalls
 before the ~49 days are over, but you can run Haskell programs
 without the timer signal, an we want it to be correct in all
 cases.

 Reviewers: bgamari, austin, hvr, NicolasT, Phyx

 Reviewed By: bgamari, Phyx

 Subscribers: syd, Phyx, rwbarton, thomie

 GHC Trac Issues: #14262

 Differential Revision: https://phabricator.haskell.org/D4011
 }}}

-- 
Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/14262#comment:6>
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