[LAU] [Jack-Devel] jack2 turned verbose

[Brendan Jones]

On 06/01/2012 03:48 PM, David Adler wrote:
> On Fri, Jun 1, 2012 at 2:52 PM, Robin Gareus wrote:
>>
>> It might have to do with Arch's compiler[-flags] and how jack2 uses
>> unions .. or scoping: JackGlobals vs Engine-Parameters.. although I
>> don't have an explanation.. all seems good.
>
> Compiler flags (for 32bit) are, (from unaltered /etc/makepkg.conf):
> CXXFLAGS="-march=i686 -mtune=generic -O2 -pipe -fstack-protector
> --param=ssp-buffer-size=4 -D_FORTIFY_SOURCE=2"
>
>> A hunch: it could be caused by using 'server_ptr->verbose.b' (a union)
>> as boolean. The sever only checks "if (server_ptr->verbose.b)". The
>> union itself comprises other uninitialized values that could make it
>> evaluate to true (though it shouldn't, but maybe some compiler
>> optimization casts it to (int) instead of (bool) )
>>
>>
>> I know this is the '-users' list (I'm ccing jack-devel), but could
>> someone who experiences the problem try to track it down?
>>
>> Basically just add a few printf()'s. Start at: common/JackControlAPI.cpp
>> - line 926 - before the call to  "new JackServer(..)" add
>>
>>   printf("DEBUG verbose: %s\n",(server_ptr->verbose.b)?"on":"off");
>>
>> recompile, launch jackd. If it prints "verbose: on", sth is wrong with
>> parameter initialization in main() or with using unions. If it's "off"
>> the problem sits deeper:
>
> DEBUG verbose: on
>
>> add a line just after common/JackServer.cpp line 66
>>   printf("DEBUG verbose2: %s\n",(JackGlobals::fVerbose)?"on":"off");
>> ...
>
> above, your line number didn't match exactly, so we seem to have
> different versions (1.9.7 here). Thus, I wasn't exactly sure where to
> add the prinf() and did the following:
>
> ...
>      JackServerGlobals::fUserCount = 1;     // One user
>      printf("DEBUG verbose2: %s\n",(JackGlobals::fVerbose)?"on":"off");
>      JackGlobals::fVerbose = verbose;
>      printf("DEBUG verbose3: %s\n",(JackGlobals::fVerbose)?"on":"off");
> }
>
> which prints:
> DEBUG verbose2: off
> DEBUG verbose3: on
>
>> A crude test for the union() hunch would be to change
>> common/JackControlAPI.h line 53:
>>   replace
>>   "union jackctl_parameter_value"
>> with
>>   "struct jackctl_parameter_value"
>> and compile with '-fpermissive' like this:
>>
>>   CXXFLAGS="-fpermissive" ./waf  configure
>>   ./waf
>>
>
> Again, mismatching line numbers. I assume you meant the line:
> union jackctl_parameter_value verbose;
>
> Changing that to struct fixes both issues I reported,
> the verbose output and exit on last client close.
>
> So we seem to be getting somewhere. Nice.
>
>
> thanks Robin,
> d

I've come a cross a jackdbus error which seems related. Basically 
jackbus receives a SIGSEGV via the dbus-daemon on account of a bool 
value not being 1 or 0.

The crude workaround below does nothing to explain the issue. Using a 
struct in this instance is also not possible:

diff -Nurp jack-1.9.8.orig/dbus/jackdbus.c jack-1.9.8/dbus/jackdbus.c
--- jack-1.9.8.orig/dbus/jackdbus.c	2011-12-19 12:54:24.000000000 +0100
+++ jack-1.9.8/dbus/jackdbus.c	2012-06-03 22:06:16.148799580 +0200
@@ -418,6 +418,7 @@ jack_dbus_message_append_variant(
      }

      /* Append the supplied value. */
+    if (type == DBUS_TYPE_BOOLEAN) *arg = (message_arg_t) ((int*)arg>0);
      if (!dbus_message_iter_append_basic (&sub_iter, type, (const void 
*) arg))
      {
          dbus_message_iter_close_container (iter, &sub_iter);

Where arg is a pointer to (dbus/jackdbus.h)
typedef union
{
     unsigned char byte;
     dbus_bool_t boolean;
     dbus_int16_t int16;
     dbus_uint16_t uint16;
     dbus_int32_t int32;
     dbus_uint32_t uint32;
     dbus_int64_t int64;
     dbus_uint64_t uint64;
     double doubl;
     const char *string;
} message_arg_t;