Main.cpp

/*
#
#    This software is Copyright by the Board of Trustees of Michigan
#    State University (c) Copyright 2005.
#
#    You may use this software under the terms of the GNU public license
#    (GPL) ir the Tcl BSD derived license  The terms of these licenses
#     are described at:
#
#     GPL:  http://www.gnu.org/licenses/gpl.txt
#     Tcl:  http://www.tcl.tk/softare/tcltk/license.html
#     Start with the second paragraph under the Tcl/Tk License terms
#     as ownership is solely by Board of Trustees at Michigan State University. 
#
#     Author:
#             Ron Fox
#	     NSCL
#	     Michigan State University
#	     East Lansing, MI 48824-1321
#
*/

/*!
  \file Main.cpp
   This file contains the unbound functions and the program entry point.
   The inventory of functions includes:
   - main          - Program entry point.
   - EpicsInit     - Perform whatever initialization EPICS requires.
   - startRepeater - Workaround to properly start/stop the caRepeater
                     process when it is not started by the system startup
                     scripts.
*/

#include <config.h>
#include "cmdline.h"
#include "CApplication.h"
#include <cadef.h>
#include <stdio.h>
#include <string.h>
#include <errno.h>
#include <unistd.h>
#include <sys/types.h>
#include <CopyrightNotice.h>
#include <Iostream.h>
#include <string>
#include <Exception.h>

#ifdef HAVE_STD_NAMESPACE
using namespace std;
#endif


/*!
   This function kludges around a problem with epics.  It's supposed
   to start up caRepeater, but evidently:
   - It does that by forking and making caRepeater the parent process.
   - the resulting caRepeater identifies to ps as us.
   - After our process exits, the resulting caRepeater doesn't work quite
     right but hangs around.


*/
void
startRepeater(int argc, char** argv)
{
  string repeatername(EPICS_BIN);
  repeatername += "/caRepeater";

  int pid = fork();
  if(pid < 0) {			// Fork failed.
    perror("Failed to fork in startRepeater()");
    exit(errno);
  }
  else if (pid == 0) {		// child process
    if(daemon(0,0) < 0) {
      perror("Child could not setsid");
      exit(errno);
    }
    argv[0]  = "caRepeater";
    int stat = execlp(repeatername.c_str(),
		      repeatername.c_str(), NULL);
    perror("Child: execlp failed!!");
    exit(errno);
  }
  else {			// Fork parent process..
    usleep(1000);			// Let it startup.
  }
}

/*!
  Initializes access to EPICS
  \throw fatal exception caught by epics
        on error.
*/
void EpicsInit(int argc, char** argv)
{

  startRepeater(argc, argv);
  int status = ca_task_initialize();
  SEVCHK(status, "Initialization failed");
  
}


/*!
  Actual program entry point.  We parse the commands and, if that's
  successful, creat an application object and invoke it.
*/
int
main(int argc, char** argv)
{
  try {
    gengetopt_args_info args;
    cmdline_parser(argc, argv, &args); // exits on error.

    // Ensure the user supplied a filename.

    if(args.inputs_num != 1) {
      cerr << "Missing channel input file.\n";
      cmdline_parser_print_help();
      exit(-1);
    }

    CopyrightNotice::Notice(cout, argv[0], 
			    "1.0", "2004");
    CopyrightNotice::AuthorCredit(cout, argv[0],
				  "Ron Fox", NULL);
    EpicsInit(argc, argv);
    CApplication app;
    int status =  app(args);
    
    // In the future, maybe app can exit correctly... so...

    if(status != 0) {
      cerr << "Main application object exiting due to error\n";
    }
    return status;
  }
  catch (string message) {
    cerr << "Main caught a string exception: " << message << endl;
    cerr << "Exiting due to string exception " << endl;
  }
  catch (CException& failure) {
    cerr << "Main caught an NSCL Exception object: " << failure.ReasonText()
         << endl;
    cerr << "Exiting due to an NSCL Exception object\n";
  }
  catch (char* msg) {
    cerr << "Main caught a char* exception: " << msg << endl;
    cerr << "Exiting due to a char* exception " << endl;
  }
  catch (...) {
    cerr << "Main caught an unanticipated exception type ... exiting \n";
  }
  exit(-1);			// Exit due to exception.
}