[stunnel-users] Possible signal handling bug in fork mode

Thu Feb 18 00:36:41 CET 2016

Hi,

I have looked further into this issue. Part of the solution would be to
reset signal disposition to SIG_DFL, either in the child after the fork, or
around the call to create_client in accept connection for the child to
inherit appropriate disposition from the start. Temporarily blocking
signals could help. I have to verify exactly how it behaves.

By the way, why is SIG_CHLD set to null_handler in create_client? The
default disposition for this signal is SIG_IGN.

Regards,

2016-02-16 11:45 GMT-05:00 Philippe Anctil <philippe.anctil at gmail.com>:

> Hi,
>
> In fork mode, sending a sigterm signal to a child is caught by the parent.
> I suspect it has something to do with signal_pipe being shared by the child
> and parent after the fork.
>
> Here I sent a signal to the parent while a child process was also running.
> The parent shut down as expected. After sending sigterm, the child remains.
>
> Processes before sigterm:
>
> UID        PID  PPID  C STIME TTY      STAT   TIME CMD
> user      1423     1  0 10:32 ?        Ss     0:00
> /usr/local/stunnel/bin/stunnel.bin /usr/local/stunnel/etc/server.conf
> user      1921  1423  0 10:37 ?        S      0:00  \_
> /usr/local/stunnel/bin/stunnel.bin /usr/local/stunnel/etc/server.conf
>
> selected pid 1423
>
> Processes after:
>
> UID        PID  PPID  C STIME TTY      STAT   TIME CMD
> user      1921     1  0 10:37 ?        S      0:00
> /usr/local/stunnel/bin/stunnel.bin /usr/local/stunnel/etc/server.conf
>
> Here I sent the signal to the child. The parent shut down and the child
> completed normally.
>
> Processes before:
>
> UID        PID  PPID  C STIME TTY      STAT   TIME CMD
> user      1276     1  0 10:31 ?        Ss     0:00
> /usr/local/stunnel/bin/stunnel.bin /usr/local/stunnel/etc/server.conf
> user      1309  1276  0 10:31 ?        S      0:00  \_
> /usr/local/stunnel/bin/stunnel.bin /usr/local/stunnel/etc/server.conf
>
> selected pid 1309
>
> Processes after:
>
> UID        PID  PPID  C STIME TTY      STAT   TIME CMD
> user      1309     1  0 10:31 ?        S      0:00
> /usr/local/stunnel/bin/stunnel.bin /usr/local/stunnel/etc/server.conf
>
> I know I should be trying threads. I will eventually. I can only switch
> once I validate it can sustain our level of traffic. Fork has done that
> flawlessly for many years now.
>
> Best regards,
>
>
> --
> Philippe Anctil
>

-- 
Philippe Anctil
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