pty: unblock all signals before exec'ing the child #10
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When we register signals in the eloop we also block them in our signal mask. The signal mask is inherited by the child. Therefore, if the child does not reset its mask (e.g. bash and most normal processes), it will not receive any of the signals that we handle. So for example C-c (SIGINT) does nothing in the child process. We now unblock all signals before we exec the child. [It's also worth noting that if we _ignore_ a signal - sigaction(SIG_IGN) - this is also inherited and we must reset it to default. However, we do not ignore signals so this is unneeded.] Here is some more discussion on signalfd and this problem: https://lwn.net/Articles/415684/ Signed-off-by: Ran Benita <ran234@gmail.com>
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Good catch. I've applied it with sigemptyset() and SIGSETMASK as I think this is more readable. Thanks! And yes, we probably need some kind of signal subsystem later if you intend to use multiple threads and/or SIGIGN and friends. However, for now its enough what we have. |
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Hi,
Thanks for merging the pty stuff. This is a fix for a problem I noticed but only now had time to look at. If you can think of a more generic solution that'd be even better, of course.
Ran