[tor-bugs] #33087 [Core Tor/Tor]: closing stdio fds on exit can interfere with LeakSanitizer, etc

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#33087: closing stdio fds on exit can interfere with LeakSanitizer, etc
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     Reporter:  catalyst      |      Owner:  (none)
         Type:  defect        |     Status:  new
     Priority:  Medium        |  Milestone:  Tor: unspecified
    Component:  Core Tor/Tor  |    Version:
     Severity:  Normal        |   Keywords:  tor-log
Actual Points:                |  Parent ID:
       Points:                |   Reviewer:
      Sponsor:                |
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 At tor exit time, `tor_log_close_sigsafe_err_fds()` winds up closing
 stderr or stdout if they're being log destinations.  This can close stderr
 before tools like LeakSanitizer can output useful information, e.g., if
 there's a config setting like `Log notice stderr`.  (valgrind doesn't seem
 to have this problem, maybe because it runs a separate process?)

 Is it correct for us to close a default fd like stderr or stdout if we're
 not running as a daemon?  Other tools that do runtime interception might
 also be affected.  If we think we have a good reason to explicitly close
 these fds, we probably should document how tor's closing of these fds can
 interfere with debugging tools.

 nickm thinks this behavior might be new in 0.4.2 with the signal safety
 work.  I haven't had time to investigate further.

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Ticket URL: <https://trac.torproject.org/projects/tor/ticket/33087>
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