Re: [diff] usr.sbin/smtpd: fix event handling upon exit

[Todd C . Miller]

OK millert@

 - todd

Re: [diff] usr.sbin/smtpd: fix event handling upon exit

[Gilles CHEHADE]

Ping ?

> On 14 Dec 2020, at 11:34, Gilles Chehade  wrote:
> 
> Hello,
> 
> Upon termination, the parent process will call parent_shutdown() which will 
> in turn call mproc_clear() to properly terminate IPC with child processes.
> 
> In mproc_clear(), event_del() is called but a check is lacking to ensure 
> event_add() was called prior to this.
> 
> On OpenBSD, this doesn’t seem to cause any issue but on other systems with a 
> different libevent, calling event_del() without a matching event_add() either 
> causes a runtime warning or a crash upon exit.
> 
> Gilles
> 
> 
> diff --git a/usr.sbin/smtpd/mproc.c b/usr.sbin/smtpd/mproc.c
> index bde229e1..dac38af2 100644
> --- a/usr.sbin/smtpd/mproc.c
> +++ b/usr.sbin/smtpd/mproc.c
> @@ -90,7 +90,8 @@ mproc_clear(struct mproc *p)
> {
>   log_debug("debug: clearing p=%s, fd=%d, pid=%d", p->name, 
> p->imsgbuf.fd, p->pid);
> 
> - event_del(>ev);
> + if (p->events)
> + event_del(>ev);
>   close(p->imsgbuf.fd);
>   imsg_clear(>imsgbuf);
> }
> 

[diff] usr.sbin/smtpd: fix event handling upon exit

[GILLES CHEHADE]

Hello,

Upon termination, the parent process will call parent_shutdown() which will in 
turn call mproc_clear() to properly terminate IPC with child processes.

In mproc_clear(), event_del() is called but a check is lacking to ensure 
event_add() was called prior to this.

On OpenBSD, this doesn’t seem to cause any issue but on other systems with a 
different libevent, calling event_del() without a matching event_add() either 
causes a runtime warning or a crash upon exit.

Gilles


diff --git a/usr.sbin/smtpd/mproc.c b/usr.sbin/smtpd/mproc.c
index bde229e1..dac38af2 100644
--- a/usr.sbin/smtpd/mproc.c
+++ b/usr.sbin/smtpd/mproc.c
@@ -90,7 +90,8 @@ mproc_clear(struct mproc *p)
{
log_debug("debug: clearing p=%s, fd=%d, pid=%d", p->name, 
p->imsgbuf.fd, p->pid);

-   event_del(>ev);
+   if (p->events)
+   event_del(>ev);
close(p->imsgbuf.fd);
imsg_clear(>imsgbuf);
}