[omniORB] Proper way for orderly server process shutdown?

[Sai-Lai Lo]

Wil,

>>>>> Wil Evers writes:

> Does anyone have some simple example code performing an orderly shutdown?
> Platform details: I'm running Linux kernel 2.0.36 with glibc2 and
> egcs-1.1.2.

The code bit below is what I used for testing, you can see I'm calling
impl_shutdown inside a oneway call so what you are doing is correct.

With regard to the the program core dump on linux, I've also seen this on
machines running glibc-2.0. It happens about once out of 20 invocations.
I cannot figure out what is causing this. However if you look at where it
SEGV under gdb, its always inside the pthread library. Since I cannot find
any wrong with the shutdown code, I've classified this one as a bug in
glibc-2.0.

I've also tested the same program on a Redhat 6.0 machine that comes with
glibc-2.1. So far I've not seen one core dump. This may be an indication
that the problem has been fixed in glibc-2.1.

On a related issue, if one do a Ctrl-C on a running linux multi-threaded
program, occasionally one gets a core dump. I still cannot figure out how
signals are handled in linux threads and whether the core dump is caused by
a bug in the thread package or I've done something silly.

-------------------
// Usage: server2 [<echo object name> <shutdown object name>]
//        names are COSNaming compound names (e.g. x/y/echo.obj)>]
//

// IDL
//    interface Shutdown {
//        oneway void off();
//    };
//

#include <iostream.h>
#include <common/common.h>
#include <echo.hh>
#include <shutdown.hh>

CORBA::BOA_ptr boa;

class Echo_i : public virtual _sk_Echo {
public:
  Echo_i() {}
  virtual ~Echo_i() { cerr << "Echo_i::~Echo_i" << endl; }
  virtual char * echoString(const char *mesg);
};

char *
Echo_i::echoString(const char *mesg) {
  char *p = CORBA::string_dup(mesg);
  return p;
}


class Shutdown_i : public virtual _sk_Shutdown {
public:
  Shutdown_i() {}
  ~Shutdown_i() { cerr << "Shutdown_i::~Shutdow_i" << endl; }
  void off() { boa->impl_shutdown(); }
};

int
main(int argc, char **argv)
{
  CORBA::ORB_ptr orb = CORBA::ORB_init(argc,argv,"omniORB2");
  boa = orb->BOA_init(argc,argv,"omniORB2_BOA");


  CosNaming::Name use_echo_name;
  CosNaming::Name use_shutdown_name;
  if (argc > 1) {
    if (argc != 3) {
      cerr << "Usage: server2 [<echo object name> <shutdown object name>]\n"
	   << "       names are COSNaming compound names (e.g. x/y/echo.obj)>]"
           << endl;
      return 1;
    }
    try {
      use_echo_name = string_to_name(argv[1]);
      use_shutdown_name = string_to_name(argv[2]);
    }
    catch (...) {
      cerr << argv[1] << " or " << argv[2]
	       << " is not a valid COS Naming compound name." << endl;
      return 1;
    }
  }

  omniORB::idleConnectionScanPeriod(omniORB::idleIncoming,15);

  Echo_i *myobj = new Echo_i;
  myobj->_obj_is_ready(boa);

  {
    Echo_var myobjRef = myobj->_this();
    if (use_echo_name.length()) {
      if (!bindObjectToName(orb,myobjRef,use_echo_name)) {
	return 1;
      }
    }
    else {
      CORBA::String_var p = orb->object_to_string(myobjRef);
      cerr << "Echo object: " << (char*)p << endl;
    }
  }

  Shutdown_i *myswitch = new Shutdown_i;
  myswitch->_obj_is_ready(boa);
  {
    CORBA::Object_var myobjRef = myswitch->_this();
	
    if (use_shutdown_name.length()) {
      if (!bindObjectToName(orb,myobjRef,use_shutdown_name)) {
	return 1;
      }
    }
    else {
      CORBA::String_var p = orb->object_to_string(myobjRef);
      cerr << "Offswitch object: " << (char*)p << endl;
    }
  }

  cerr << "Main thread calling BOA is ready..." << endl;
  boa->impl_is_ready();
  cerr << "Main thread returns from BOA is ready..." << endl;
  myobj->_dispose();
  myswitch->_dispose();
  cerr << "Removing BOA..." << endl;
  boa->destroy();
  cerr << "BOA has been removed.." << endl;
  return 0;
}









-- 
Sai-Lai Lo                                   S.Lo@uk.research.att.com
AT&T Laboratories Cambridge           WWW:   http://www.uk.research.att.com 
24a Trumpington Street                Tel:   +44 1223 343000
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