[Python-Dev] Python threads end up blocking signals in subprocesses (original) (raw)

Martin v. Löwis martin at v.loewis.de
Sun Dec 21 05:27:45 EST 2003

Michael Hudson <mwh at python.net> writes:

> I'm not sure what to do about this: We apparently want the signals > blocked in the thread, but we don't want them to be blocked in the > process invoked through system(). Proposals are welcome.

Does pthreadatfork() help?

Most likely. system(3) is specified as being implemented through fork()/exec(), so an atfork handler should be invoked in any compliant implementation. We could install a child handler, which unblocks the signals we don't want to be blocked.

Now, the question is: What signals precisely we don't want to be blocked? I think the answer is "All signals that have not explicitly been blocked by the application".

OTOH, we already have PyOS_AfterFork, which could be used instead of pthread_atfork. Jeff, would you like to add some code there, to set all signal handlers into default for which Handlers lists that the default handling should occur?

Regards, Martin

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