Bug 2124488

+++ This bug was initially created as a clone of Bug #2070496 +++

Version-Release number of selected component (if applicable):

rsyslog-8.2102.0-5.el8.x86_64
bash-4.4.20-2.el8.x86_64



#cat /etc/logrotate.d/syslog

/var/log/cron
/var/log/maillog
/var/log/messages
/var/log/secure
/var/log/spooler
{
    missingok
    sharedscripts
    postrotate
        /usr/bin/systemctl kill -s HUP rsyslog.service >/dev/null 2>&1 || true
    endscript
}



How reproducible:



[root@rhel85 ~]# echo $POSIXLY_CORRECT

[root@rhel85 ~]# /usr/bin/systemctl kill -s HUP rsyslog.service
[root@rhel85 ~]# systemctl status rsyslog.service
● rsyslog.service - System Logging Service
   Loaded: loaded (/usr/lib/systemd/system/rsyslog.service; enabled; vendor preset: enabled)
   Active: active (running) since Thu 2022-03-31 11:18:04 CEST; 10min ago
     Docs: man:rsyslogd(8)
           https://www.rsyslog.com/doc/
 Main PID: 877 (rsyslogd)
    Tasks: 3 (limit: 23464)
   Memory: 2.5M
   CGroup: /system.slice/rsyslog.service
           └─877 /usr/sbin/rsyslogd -n

Mar 31 11:18:04 rhel85.example.com systemd[1]: Starting System Logging Service...
Mar 31 11:18:04 rhel85.example.com systemd[1]: Started System Logging Service.
Mar 31 11:18:04 rhel85.example.com rsyslogd[877]: [origin software="rsyslogd" swVersion="8.2102.0-5.el8" x-pid=">
Mar 31 11:18:04 rhel85.example.com rsyslogd[877]: imjournal: journal files changed, reloading...  [v8.2102.0-5.e>
Mar 31 11:22:23 rhel85.example.com rsyslogd[877]: [origin software="rsyslogd" swVersion="8.2102.0-5.el8" x-pid=">
Mar 31 11:28:12 rhel85.example.com rsyslogd[877]: [origin software="rsyslogd" swVersion="8.2102.0-5.el8" x-pid=">



[root@rhel85 ~]# export POSIXLY_CORRECT=1

[root@rhel85 ~]# /usr/bin/systemctl kill -s HUP rsyslog.service
Failed to kill unit -s.service: Unit -s.service not loaded.
Failed to kill unit HUP.service: Unit HUP.service not loaded.

[root@rhel85 ~]# systemctl status rsyslog.service
● rsyslog.service - System Logging Service
   Loaded: loaded (/usr/lib/systemd/system/rsyslog.service; enabled; vendor preset: enabled)
   Active: inactive (dead) since Thu 2022-03-31 11:28:47 CEST; 4s ago
     Docs: man:rsyslogd(8)
           https://www.rsyslog.com/doc/
  Process: 877 ExecStart=/usr/sbin/rsyslogd -n $SYSLOGD_OPTIONS (code=exited, status=0/SUCCESS)
 Main PID: 877 (code=exited, status=0/SUCCESS)

Mar 31 11:18:04 rhel85.example.com systemd[1]: Starting System Logging Service...
Mar 31 11:18:04 rhel85.example.com systemd[1]: Started System Logging Service.
Mar 31 11:18:04 rhel85.example.com rsyslogd[877]: [origin software="rsyslogd" swVersion="8.2102.0-5.el8" x-pid=">
Mar 31 11:18:04 rhel85.example.com rsyslogd[877]: imjournal: journal files changed, reloading...  [v8.2102.0-5.e>
Mar 31 11:22:23 rhel85.example.com rsyslogd[877]: [origin software="rsyslogd" swVersion="8.2102.0-5.el8" x-pid=">
Mar 31 11:28:12 rhel85.example.com rsyslogd[877]: [origin software="rsyslogd" swVersion="8.2102.0-5.el8" x-pid=">
Mar 31 11:28:47 rhel85.example.com rsyslogd[877]: [origin software="rsyslogd" swVersion="8.2102.0-5.el8" x-pid=">
Mar 31 11:28:47 rhel85.example.com rsyslogd[877]: [origin software="rsyslogd" swVersion="8.2102.0-5.el8" x-pid=">
Mar 31 11:28:47 rhel85.example.com systemd[1]: rsyslog.service: Succeeded.

--- Additional comment from Attila Lakatos on 2022-04-05 11:47:49 UTC ---

Hello,

To me, it does not seem like a bug in rsyslog, when the POSIXLY_CORRECT=1 env variable is set.
If you take a look at the command output lines:
Failed to kill unit -s.service: Unit -s.service not loaded.
Failed to kill unit HUP.service: Unit HUP.service not loaded.

You can see that it is not capable of determining which parameter represents the signal. Firstly, it tries the "-s.service"(don't know why), which probably does not exist. From the systemctl man page: --signal: When used with kill, choose which signal to send to selected processes. Must be one of the well-known signal specifiers such as SIGTERM, SIGINT or SIGSTOP. If omitted, defaults to SIGTERM.
As it was unable to process the signal part, the default is used, which is the SIGTERM signal. In that case, it is delivered to the rsyslog service. Thus, rsyslog will terminate.

Feel free to correct me if I am wrong.

--- Additional comment from Dariusz Wojewódzki on 2022-04-06 08:08:14 UTC ---

Hello, This command is in the official rsyslog package in the /etc/logrotate.d/syslog file.

As you stated, systemctl wants to kill both the -s and HUP services that do not exist and sends a SIGTERM signal to all parameters after kill, rather than interpreting -s as a switch.

On the other hand:
 "/usr/bin/systemctl -s HUP kill rsyslog.service >/dev/null 2>&1 || true" works with POSIXLY_CORRECT.

--- Additional comment from Attila Lakatos on 2022-04-07 08:38:23 UTC ---

Hello,

Now I can see the difference between the two commands:
1.  /usr/bin/systemctl kill -s HUP rsyslog.service
2.  /usr/bin/systemctl -s HUP kill rsyslog.service

So in case the POSIXLY_CORRECT=1 env var is set, only the second option is correct. Both versions work when the mentioned env variable is not set. Although I do not know the reason behind it.

According to the manual page, the syntax should be the following:
  systemctl [OPTIONS...] COMMAND [NAME...]

Thanks for noticing it.