Messages in this thread | | | Subject | Re: [PATCH 1/7] signal.h: Define SIGINFO on all architectures | From | Rob Landley <> | Date | Mon, 10 Jun 2019 16:10:39 -0500 |
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On 6/5/19 3:19 AM, Arseny Maslennikov wrote: > This complementary patch defines SIGINFO as a synonym for SIGPWR > on every architecture supported by the kernel. > The particular signal number chosen does not really matter and is only > required for the related tty functionality to work properly, > so if it does not suite expectations, any suggestions are warmly > welcome.
This was the problem I saw last month: 32 bits worth of signal numbers already defined, gotta alias something.
> SIGPWR looks like a nice candidate for this role, because it is > defined on every supported arch; it is currently only used to inform > PID 1 of power failures, and daemons that care about low-level > events do not tend to have a controlling terminal.
/dev/console isn't a controlling tty so ctrl-T wouldn't send SIGPWR to PID 1 anyway.
> However, on sparcs SIGPWR is a synonym for SIGLOST, a signal unique > to that architecture, with a narrow set of intended uses that do not > combine well with interactively requesting status. > SIGLOST is not used by any kernel code at the moment. > I'm not sure there is a more reasonable alternative right now.
The fact it's already _been_ aliased once says it's a good candidate for it. The easy solution is don't support SIGINFO on sparc until the sparc guys figure out what to do there and add sparc support in a follow-up patch.
Rob
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