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https://issues.apache.org/jira/browse/MESOS-8170?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16237988#comment-16237988
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James Peach commented on MESOS-8170:
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/cc [~benjaminhindman] [~jieyu]
> Propagate exit status 127 for errors after fork
> -----------------------------------------------
>
> Key: MESOS-8170
> URL: https://issues.apache.org/jira/browse/MESOS-8170
> Project: Mesos
> Issue Type: Bug
> Components: libprocess
> Reporter: James Peach
>
> There's no consistent methodology in lib process or Mesos for propagating
> errors that happen between fork and exec. For
> [posix_spawn|http://pubs.opengroup.org/onlinepubs/009695399/functions/posix_spawn.html],
> the POSIX standard designated an exit code or 127 to identify this case. We
> should adopt the same convention.
> {quote}
> The 8 bits of child process exit status that are guaranteed by IEEE Std
> 1003.1-2001 to be accessible to the waiting parent process are insufficient
> to disambiguate a spawn error from any other kind of error that may be
> returned by an arbitrary process image. No other bits of the exit status are
> required to be visible in stat_val, so these macros could not be strictly
> implemented at the library level. Reserving an exit status of 127 for such
> spawn errors is consistent with the use of this value by system() and popen()
> to signal failures in these operations that occur after the function has
> returned but before a shell is able to execute. The exit status of 127 does
> not uniquely identify this class of error, nor does it provide any detailed
> information on the nature of the failure. Note that a kernel implementation
> of posix_spawn() or posix_spawnp() is permitted (and encouraged) to return
> any possible error as the function value, thus providing more detailed
> failure information to the parent process.
> Thus, no special macros are available to isolate asynchronous posix_spawn()
> or posix_spawnp() errors. Instead, errors detected by the posix_spawn() or
> posix_spawnp() operations in the context of the child process before the new
> process image executes are reported by setting the child's exit status to
> 127. The calling process may use the WIFEXITED and WEXITSTATUS macros on the
> stat_val stored by the wait() or waitpid() functions to detect spawn failures
> to the extent that other status values with which the child process image may
> exit (before the parent can conclusively determine that the child process
> image has begun execution) are distinct from exit status 127.
> {quote}
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