lib/59146: POSIX.1-2024: async-signal-safety audit

[campbell+netbsd%mumble.net@localhost]

>Number:         59146
>Category:       lib
>Synopsis:       POSIX.1-2024: async-signal-safety audit
>Confidential:   no
>Severity:       serious
>Priority:       medium
>Responsible:    lib-bug-people
>State:          open
>Class:          sw-bug
>Submitter-Id:   net
>Arrival-Date:   Thu Mar 06 14:00:01 +0000 2025
>Originator:     Taylor R Campbell
>Release:        current, 10, 9, ...
>Organization:
The Async-signal-safeBSD Forkation
>Environment:
>Description:
The list of functions required by POSIX.1-2024 to be async-signal-safe is here:

https://pubs.opengroup.org/onlinepubs/9799919799/functions/V2_chap02.html#tag_16_04_03

We should review the list of functions in the sigaction(2) man page to make sure there's nothing missing (https://man.NetBSD.org/sigaction.2), and audit them to make sure they are async-signal-safe.

We can, of course, add our own functions to the list if we want to provide stronger guarantees than POSIX does.
>How-To-Repeat:
standards inspection

https://pubs.opengroup.org/onlinepubs/9799919799/functions/V2_chap02.html#tag_16_04_03
>Fix:
Yes, please!