[tor-bugs] #20239 [Applications/Tor Browser]: Tor Browser should print error messages on startup failure

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#20239: Tor Browser should print error messages on startup failure
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     Reporter:  cypherpunks               |      Owner:  tbb-team
         Type:  enhancement               |     Status:  new
     Priority:  Medium                    |  Milestone:
    Component:  Applications/Tor Browser  |    Version:
     Severity:  Normal                    |   Keywords:
Actual Points:                            |  Parent ID:
       Points:                            |   Reviewer:
      Sponsor:                            |
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 This is related to #20238 (and #20237 and #19851). When the Browser failed
 to start, it produced absolutely no output. It just exited with an error
 status like 134, which luckily I was able to see because my $PS1 includes
 $?.

 I understand you don't want the browser leaking data into .xsession-errors
 or whatever, but this is clearly not the ideal way to do it. Nobody who's
 unfamiliar with Unix debugging would figure out what's happening.

 Could you redirect these fds later in the startup process? I don't know if
 the Browser uses fork()--it would have to happen before that, and
 obviously before any network access might happen. You'd need to do
 something like this in the C code:
 fd=open("/dev/null",O_WRONLY|O_CLOEXEC); dup2(fd, 1); dup2(fd, 2);
 close(fd); but with proper error checking.

 Even better, write a wrapper process that does *not* use ASan or other
 experimental features, that will execute the browser and pop a GUI window
 with stdout/stderr text on a nonzero exit status. And offer to restart it,
 like the Browser does when Tor crashes. Maybe even try to detect what's
 wrong--using the error text, or exit status, or by "unit-testing" some
 features that have caused trouble in the past--and work around it or
 suggest the fix.

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Ticket URL: <https://trac.torproject.org/projects/tor/ticket/20239>
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