[tor-bugs] #9781 [Tor]: Tor with port forwarding shows "Failed to terminate process" messages

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#9781: Tor with port forwarding shows "Failed to terminate process" messages
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     Reporter:           |      Owner:
  mgorbach               |     Status:  needs_review
         Type:  defect   |  Milestone:  Tor: 0.2.5.x-final
     Priority:  normal   |    Version:
    Component:  Tor      |   Keywords:  tor-relay tor-fw-helper 025-triaged
   Resolution:           |  Parent ID:
Actual Points:           |
       Points:           |
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Changes (by nickm):

 * status:  new => needs_review


Comment:

 The "Failed to terminate process with PID '%s'" is almost certainly a
 duplicate of #8746 : our "destroy a process" logic was really screwy.

 I can reproduce that error by starting without a working tor-fw-helper.
 Does the message go away when you set "portforwardinghelper /path/to/tor-
 fw-helper "?  (Replace the path with a real path.)  If so, then this bug
 isn't caused by a problem in tor-fw-helper.

 The remaining problem is that the error message here is completely
 useless.  We're supposed to catch the error message ("ERR: Failed to spawn
 background process...") in log_from_pipe, but we don't.

 And ''that'' happens because log_from_pipe() assumes that if the first
 read() we do gives us EAGAIN, we haven't gotten the error message.  (!)

 I've got a fix for the bad error message issue in branch "bug9781".  But I
 think that fix isn't right: when I try 0.2.3, the error message is
 correct, which makes me think we made these files nonblocking while we
 were doing pluggable transport work in 0.2.4.  Bisecting...

--
Ticket URL: <https://trac.torproject.org/projects/tor/ticket/9781#comment:7>
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