bin/59929: blocklistd stops working with 'no message (Message too long)'

["spz%NetBSD.org@localhost via gnats" <gnats-admin%NetBSD.org@localhost>]

>Number:         59929
>Category:       bin
>Synopsis:       blocklistd stops working with 'no message (Message too long)'
>Confidential:   no
>Severity:       serious
>Priority:       medium
>Responsible:    bin-bug-people
>State:          open
>Class:          sw-bug
>Submitter-Id:   net
>Arrival-Date:   Sun Jan 18 09:05:00 +0000 2026
>Originator:     S.P.Zeidler
>Release:        NetBSD 11.0_BETA
>Organization:
	TNF
>Environment:
System: NetBSD shadow.netbsd.org 11.0_BETA NetBSD 11.0_BETA (SHADOW) #0: Thu Nov 6 06:19:38 UTC 2025 spz%franklin.NetBSD.org@localhost:/home/netbsd/11/amd64/obj/sys/arch/amd64/compile/SHADOW amd64
Architecture: x86_64
Machine: amd64

also happens on NetBSD 11.0_BETA/sparc64 with Jan 11th netbsd-11

>Description:
syslog says:
Jan  1 08:03:53 shadow blocklistd[1439]: processing type=1 fd=1020 remote=209.97.134.59:467
46 msg="ssh" uid=0 gid=0
Jan  1 08:03:53 shadow blocklistd[1439]: blocked 209.97.134.59/32:22 for 3600 seconds
Jan  1 08:08:35 shadow blocklistd[1439]: processing type=1 fd=1021 remote=199.233.217.206:6
5249 msg="sshd" uid=0 gid=0
Jan  1 08:11:27 shadow blocklistd[1439]: processing type=1 fd=1022 remote=2.57.121.112:1919
0 msg="ssh" uid=0 gid=0
Jan  1 08:11:44 shadow blocklistd[1439]: processing type=1 fd=1023 remote=45.148.10.121:356
02 msg="ssh" uid=0 gid=0
Jan  1 08:13:35 shadow blocklistd[1439]: no message (Message too long)
Jan  1 08:17:36 shadow blocklistd[1439]: no message (Message too long)
Jan  1 08:17:36 shadow blocklistd[1439]: no message (Message too long)
Jan  1 08:17:36 shadow blocklistd[1439]: no message (Message too long)
Jan  1 08:22:35 shadow blocklistd[1439]: popen /libexec/blocklistd-helper failed (Too many 
open files)
Jan  1 08:22:35 shadow blocklistd[1439]: released 193.32.162.151/32:22 after 3600 seconds
Jan  1 08:23:35 shadow blocklistd[1439]: no message (Message too long)
Jan  1 08:25:07 shadow blocklistd[1439]: no message (Message too long)
Jan  1 08:28:36 shadow blocklistd[1439]: no message (Message too long)

and no more blockable 'explorers' get blocked. Note the fd growing monotonical and
the dysfunction appearing when the descriptors limit is reached.

>How-To-Repeat:
	wait, be 'explored'
>Fix: