Return to proxy_comm.c CVS log

Up to [Pegasus] / pegasus / src / Pegasus / ProviderManager2 / CMPIR

PEP#: 130
TITLE: Remote CMPI support

DESCRIPTION: Base code for Remote CMPI

//%2003////////////////////////////////////////////////////////////////////////
//
// Copyright (c) 2000, 2001, 2002  BMC Software, Hewlett-Packard Development
// Company, L. P., IBM Corp., The Open Group, Tivoli Systems.
// Copyright (c) 2003 BMC Software; Hewlett-Packard Development Company, L. P.;
// IBM Corp.; EMC Corporation, The Open Group.
//
// Permission is hereby granted, free of charge, to any person obtaining a copy
// of this software and associated documentation files (the "Software"), to
// deal in the Software without restriction, including without limitation the
// rights to use, copy, modify, merge, publish, distribute, sublicense, and/or
// sell copies of the Software, and to permit persons to whom the Software is
// furnished to do so, subject to the following conditions:
//
// THE ABOVE COPYRIGHT NOTICE AND THIS PERMISSION NOTICE SHALL BE INCLUDED IN
// ALL COPIES OR SUBSTANTIAL PORTIONS OF THE SOFTWARE. THE SOFTWARE IS PROVIDED
// "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT
// LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR
// PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT
// HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN
// ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
// WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
//
//==============================================================================
//
// Author: Frank Scheffler
//
// Modified By:  Adrian Schuur (schuur@de.ibm.com)
//
//%/////////////////////////////////////////////////////////////////////////////

/*!
  \file proxy_comm.c
  \brief Proxy Provider communication layer handling.

  This module provides the functionality to load and manage communication
  layers, as requested by the proxy provider. These are required to
  communicate with remote providers.

  \author Frank Scheffler
*/

#include <stdio.h>
#include <stdlib.h>
#include <dlfcn.h>
#include <string.h>
#include <error.h>
#include <errno.h>
#include "proxy.h"
//#include "tool.h"
#include "debug.h"

extern CMPIBrokerExtFT *CMPI_BrokerExt_Ftab;
#define INIT_LOCK(l) if (l==NULL) l=CMPI_BrokerExt_Ftab->newMutex(0);

static void * _load_lib ( const char * libname )
{
  char filename[255];
  sprintf ( filename, "lib%s.so", libname );
  return dlopen ( filename, RTLD_LAZY );
}


//! Loads a server-side communication layer library.
/*!
  The function tries to load "lib<id>.so" looking for an entry point
  "<id>_InitCommLayer". The latter one is called to obtain a provider_comm
  structure including the function pointer table for MI calls towards
  remote providers.

  \param id the name of the comm-layer for which the library has to be loaded.
  \param broker broker handle as passed to the init function.
  \param ctx context as passed to the init function.

  \return pointer to the provider_comm structure from the comm-layer, or NULL.
 */
static provider_comm * load_comm_library ( const char * id,
					   CMPIBroker * broker,
					   CMPIContext * ctx )
{
	void * hLibrary;

	TRACE_VERBOSE(("entered function."));
	TRACE_NORMAL(("loading comm-layer library: lib%s.so", id));

	hLibrary = _load_lib ( id );

	if ( hLibrary != NULL ) {
		char function[255];
		INIT_COMM_LAYER fp;
		sprintf ( function, "%s_InitCommLayer", id );
		fp = (INIT_COMM_LAYER) dlsym ( hLibrary, function );

		if ( fp != NULL ) {
			provider_comm * result = fp ( broker, ctx );
			result->id = strdup ( id );

			TRACE_INFO(("comm-layer successfully initialized."));
			TRACE_VERBOSE(("leaving function."));
			return result;
		}

		dlclose ( hLibrary );
	}

	error_at_line ( 0, 0, __FILE__, __LINE__,
			"Unable to load/init communication-layer library: %s",
			dlerror () );

	TRACE_VERBOSE(("leaving function."));
	return NULL;
}




//! Looks up a server-side communication layer or loads it, if necessary.
/*!
  The function maintains a list of previously loaded comm-layers locally.
  A mutex is used to ensure proper access to this list. If a comm-layer
  cannot be found within the list, it is being loaded and inserted at
  the begininng.

  \param comm_id the name of the communication layer to be looked up.
  \param broker broker handle as passed to the init function.
  \param ctx context as passed to the init function.

  \return the comm-layer matching the id or NULL if it cannot be loaded.
 */
provider_comm * load_provider_comm ( const char * comm_id,
				     CMPIBroker * broker,
				     CMPIContext * ctx )
{
	static provider_comm * __comm_layers = NULL;
        static CMPI_MUTEX_TYPE __mutex=NULL;
	provider_comm * tmp;

	TRACE_VERBOSE(("entered function."));
	TRACE_NORMAL(("loading remote communication layer: %s", comm_id ));

        INIT_LOCK(__mutex);
        CMPI_BrokerExt_Ftab->lockMutex(__mutex);

	for ( tmp = __comm_layers; tmp != NULL; tmp = tmp->next ) {

		if ( strcmp ( tmp->id, comm_id ) == 0 ) {
                        CMPI_BrokerExt_Ftab->unlockMutex(__mutex);

			TRACE_INFO(("found previously loaded comm-layer."));
			TRACE_VERBOSE(("leaving function."));
			return tmp;
		}
	}

	tmp = load_comm_library ( comm_id, broker, ctx );

	if ( tmp != NULL ) {
		tmp->next     = __comm_layers;
		__comm_layers = tmp;
	}

        CMPI_BrokerExt_Ftab->unlockMutex(__mutex);

	TRACE_VERBOSE(("leaving function."));
  	return tmp;
}



/****************************************************************************/

/*** Local Variables:  ***/
/*** mode: C           ***/
/*** c-basic-offset: 8 ***/
/*** End:              ***/