Workaround for os-squid SIGSEGV

[kravietz]

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Describe the bug
The Squid service crashes with SIGSEGV when trying to shut it down using its "native" squid -k shutdown command, resulting in Squid process persisting in memory and not really shutting down. This also renders all service restart attempts ineffective. This incorrect behaviour only happens when using the -k shutdown command, but sending it SIGTERM results in a proper shutdown.

To Reproduce
Run service squid stop, watch the logs:

<13>1 2025-01-24T12:03:01+00:00 hostname kernel - - [meta sequenceId="2"] <6>pid 68937 (squid), jid 0, uid 100: exited on signal 11 (no core dump - bad address)

But if you then check ps axuw|grep squid and the Squid process will be still resident in memory.

Expected behavior
The bug can be easily mitigated by commenting out the stop_precmd definition from /usr/local/etc/rc.d/squid which will revert it to the native FreeBSD behaviour of sending SIGTERM, to which Squid surprisingly responds with proper shutdown:

...
start_postcmd=squid_getpid
#stop_precmd=squid_prestop
configtest_cmd=squid_configtest
...

The stop_precmd workaround works for me, but if it wouldn't then there's two more options to clean up the Squid process:

• sig_stop="KILL"
• stop_postcmd="pkill -9 squid"

Please note that because the Squid service script uses squid_prestop which crashes on SIGSEGV, the script is abruptly terminated and does not continue to the stop phase. This will render the above options useless as long the original squid_prestop remains in place.

Additional context
This was first reported and should mitigate this bug: #3827

Environment

• OPNsense 24.7.12_2 (amd64)
• os-squid 1.1_1
• squid 6.12

[fichtner]

For the FreeBSD port that seems to be standard behaviour:

squid_prestop()                                                                 
{                                                                               
    command_args="$command_args -k shutdown"                                
    squid_configtest                                                        
}  

Overriding stop_precmd is not possible from our end.

[kravietz]

@fichtner Yes, it is standard behaviour that causes SIGSEGV. Created freebsd/freebsd-ports#339 for upstream fix.