[Boost-bugs] [Boost C++ Libraries] #13139: child::join() incorrectly throws `waitpid(2) failed: No child processes` if child exited abnormally

Subject: [Boost-bugs] [Boost C++ Libraries] #13139: child::join() incorrectly throws `waitpid(2) failed: No child processes` if child exited abnormally
From: Boost C++ Libraries (noreply_at_[hidden])
Date: 2017-07-27 19:46:16

#13139: child::join() incorrectly throws `waitpid(2) failed: No child processes` if
child exited abnormally
------------------------------+---------------------
 Reporter:  keithb@…          |      Owner:  (none)
     Type:  Bugs              |     Status:  new
Milestone:  To Be Determined  |  Component:  process
  Version:  Boost 1.64.0      |   Severity:  Problem
 Keywords:                    |
------------------------------+---------------------
 Create a child process. Let it die abnormally (for example, calling
 `kill(getpid(), SIGABRT)` in the child). In the parent, call
 `child.join()`.

 It appears that the `::waitpid` loop in
 `boost::process::detail::posix::wait` at
 github.com/boostorg/process/blob/boost-1.64.0/include/boost/process/detail/posix/wait_for_exit.hpp#L26-L31
 only checks that the child ended because of a call to `::exit()` and does
 not check for exiting via signal (`WIFSIGNALED()`).

 Because `WIFSIGNALED()` is true, `WIFEXITED()` is false; and because it's
 false, the loop will continue and call `::waitpid()` again... this time
 with a child PID to a process which has already been reaped. `waitpid()`
 will report an error (indicating that there's no such child prcess), and
 the error will be thrown.

 The child's exact reason for exiting is lost, which is why I believe this
 should be marked a "Showstopper" severity; a workaround would be to avoid
 calling `boost::process::wait()` in any fashion and to instead use a
 custom waitpid loop using the `child.native_handle()`.

-- 
Ticket URL: <https://svn.boost.org/trac10/boost/ticket/13139>
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