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From: Leah Neukirchen <leah@vuxu.org>
To: supervision@list.skarnet.org
Subject: runit: why ignore SIGCONT for stages?
User-Agent: Gnus/5.13 (Gnus v5.13) Emacs/27.2 (gnu/linux)
Date: Tue, 23 Nov 2021 13:17:58 +0100
Message-ID: <87tug3vzex.fsf@vuxu.org>
MIME-Version: 1.0
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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@vuxu.org>  https://leahneukirchen.org/