runit: why ignore SIGCONT for stages?

From: Leah Neukirchen <leah_at_vuxu.org>
Date: Tue, 23 Nov 2021 13:17:58 +0100

Hello,

During debugging a ksh issue (https://github.com/ksh93/ksh/issues/301),
we noticed that many processes on a Void Linux system booted with runit
are ignoring SIGCONT. This seems to be due to runit(8) before execing
into the stages:

      sig_unblock(sig_cont);
      sig_ignore(sig_cont);
...
      strerr_warn3(INFO, "enter stage: ", stage[st], 0);
      execve(*prog, (char *const *)prog, envp);

This code has been there since 2001. Can someone explain why?
Ignoring SIGCONT seems to be a no-op, and the default handler seems to
create no problems for other init systems.

Thanks,

-- 
Leah Neukirchen  <leah_at_vuxu.org>  https://leahneukirchen.org/

Received on Tue Nov 23 2021 - 13:17:58 CET