[PATCH] Reminder for uhttpd: Fix potential SIGSEGV on /ubus/subscribe/ disconnect (Fixes: #1)

[Tito Brasolin]

Hello everyone,

I am writing to follow up on Pull Request (#18) I opened on GitHub a few 
months ago for the uhttpd daemon.

The patch resolves a critical stability issue (documented in issue #1) 
that causes a potential **SIGSEGV** (Segmentation Fault) when an HTTP 
client disconnects from a **/ubus/subscribe/...** endpoint without first 
explicitly unsubscribing.

The fix ensures that the ubus subscriber is properly unregistered in a 
cleanup handler, preventing subsequent callbacks from referencing freed 
client structures. This is vital for the reliable operation of the 
Server-Sent Events (SSE) functionality introduced in 2020.

* References:
     * Pull Request: https://github.com/openwrt/uhttpd/pull/18
     * Related Issue: https://github.com/openwrt/uhttpd/issues/1
     * Original SSE Patch (2020): 
https://lists.openwrt.org/pipermail/openwrt-devel/2020-September/031396.html

I understand core maintainers have limited time, and I would greatly 
appreciate it if someone could review this PR at their convenience. I am 
ready to receive feedback and make any necessary revisions.

Thank you for your time and for the great work on OpenWrt.

Best regards,

Tito Brasolin
tito.brasolin at gmail.com