[sheepdog] [PATCH] call a default signal handler in crash_handler()

[MORITA Kazutaka]

At Fri, 12 Apr 2013 15:17:28 +0800,
Liu Yuan wrote:
> 
> On 04/12/2013 03:11 PM, MORITA Kazutaka wrote:
> > Do you mean crash_handler() in logger.c?  The re-raised signal will be
> > sent to itself (the logger process), so it doesn't terminate sheep.
> > The string should be "default handler for signal xxx didn't terminate
> > the logger process"?
> 
> All three crash_handler() will call exit finally, so why logger process
> isn't terminated by that exit()?

Hmm, I don't get your point.  The logger crash_handler works as same
as the sheep and collie crash_handler do.

--- a/lib/logger.c
+++ b/lib/logger.c
@@ -489,6 +489,14 @@ static notrace void crash_handler(int signo)
        log_flush();
        closelog();
        free_logarea();
+
+       if (signo != SIGHUP) {
+               raise(signo);
+
+               sd_printf(SDOG_EMERG,
+                         "signal (%s) didn't terminate the process.",
+                         strsignal(signo));
+       }
        exit(1);
 }        

signo!=SIGHUP means that the signal was raised because of the logger
problem.  Then, the crash_handler() re-raises the signal to dump a
core file and exit.  If something unexpected happens, the logger
process doesn't terminate in the default signal handler.  Then, the
logger notifies it to the user and exits in crash_handler.  If the
default handler works as expected, sd_printf and exit aren't called at
all.

When SIGHUP is raised (this means that sheep exits unexpectedly), the
logger works as before.

Thanks,

Kazutaka