misc/58921: Audit signal handlers in tests

[campbell+netbsd%mumble.net@localhost]

>Number:         58921
>Category:       misc
>Synopsis:       Audit signal handlers in tests
>Confidential:   no
>Severity:       serious
>Priority:       medium
>Responsible:    misc-bug-people
>State:          open
>Class:          sw-bug
>Submitter-Id:   net
>Arrival-Date:   Thu Dec 19 17:50:01 +0000 2024
>Originator:     Taylor R Campbell
>Release:        current, 10, 9, ...
>Organization:
The TestBSD Signalsafoundation
>Environment:
>Description:
Various tests establish signal handlers that do things they shouldn't:

1. Syscalls without saving and restoring errno.
2. Writing to objects of types other than sig_atomic_t which may be read or written by the interrupted code.
3. printf or fprintf instead of vsnpprintf_ss and write
>How-To-Repeat:
code inspection
>Fix:
Audit everything turned up by this for bad signal handlers:

grep -rw -e sigaction -e signal tests/

(For that matter, maybe we should audit the non-test applications too!)