[PATCH] signal handlers setup

[Greg Banks]

On 11/10/11 16:57, Bron Gondwana wrote:
> On Tue, Oct 11, 2011 at 02:51:25AM +0200, Thomas Cataldo wrote:
>> While testing some java code that executes cyrus init script, I came into a
>> problem : the Java VM blocks SIGQUIT, event when using -Xrs parameter.
> 
> Why Java?

That's your bug right there :)

> 
>> As SIGQUIT is safe shutdown, I need the signal delivered correctly. I came
>> up with the attached patch that resets the signal mask for cyrmaster before
>> setting the signal handlers.
>>
>> diff --git a/master/master.c b/master/master.c
>> index 823be06..f2ca72e 100644
>> --- a/master/master.c
>> +++ b/master/master.c
>> @@ -1064,7 +1064,11 @@ void sigalrm_handler(int sig __attribute__((unused)))
>>  void sighandler_setup(void)
>>  {
>>      struct sigaction action;
>> -
>> +    sigset_t all_signals;
>> +
>> +    sigfillset(&all_signals);
>> +    sigprocmask(SIG_UNBLOCK, &all_signals, NULL);
>> +
>>      sigemptyset(&action.sa_mask);
>>      action.sa_flags = 0;
> 
> Greg - you know signal handling better than me.  What do you think?
> 

Patch looks fine, thanks Thomas.

FWIW I don't see any point explicitly unblocking all the signals,
including ones other than the ones we're about to explicitly setup
handlers for, but that's probably harmless.

Also, as a defensive programming measure it's probably a good idea to
memset() that struct sigaction to zero rather than explicitly initialise
some of its members.

-- 
Greg.