GSSAPI Client Example: main() Function

As with all C programs, the outer shell of the program is contained in the entry-point function, main(). main() performs four functions:

• Parses command-line arguments and assigns the arguments to variables.

• Calls parse_oid() to create a GSS-API OID, object identifier, if a mechanism other than the default is to be used. The object identifier comes from the name of the security mechanism, provided that a mechanism name has been supplied.

• Calls call_server(), which does the actual work of creating a context and sending data.

• Releases the storage space for the OID if necessary, after the data is sent.

The source code for the main() routine is shown in the following example.

int main(argc, argv)
     int argc;
     char **argv;
{
     char *msg;
     char service_name[128]; 
     char hostname[128];  
     char *mechanism = 0;
     u_short port = 4444;
     int use_file = 0;
     OM_uint32 deleg_flag = 0, min_stat;
     
     display_file = stdout;

     /* Parse command-line arguments. */

        argc--; argv++;
     while (argc) {
          if (strcmp(*argv, "-port") == 0) {
               argc--; argv++;
               if (!argc) usage();
               port = atoi(*argv);
          } else if (strcmp(*argv, "-mech") == 0) {
               argc--; argv++;
               if (!argc) usage();
               mechanism = *argv;
          } else if (strcmp(*argv, "-d") == 0) {
               deleg_flag = GSS_C_DELEG_FLAG;
          } else if (strcmp(*argv, "-f") == 0) {
               use_file = 1;
          } else
               break;
          argc--; argv++;
     }
     if (argc != 3)
          usage();

     if (argc > 1) {
                strcpy(hostname, argv[0]);
        } else if (gethostname(hostname, sizeof(hostname)) == -1) {
                        perror("gethostname");
                        exit(1);
        }


     if (argc > 2) { 
        strcpy(service_name, argv[1]);
        strcat(service_name, "@");
        strcat(service_name, hostname);
 
     }

      msg = argv[2];

     /* Create GSSAPI object ID. */
     if (mechanism)
         parse_oid(mechanism, &g_mechOid);

     /* Call server to create context and send data. */
     if (call_server(hostname, port, g_mechOid, service_name,
                   deleg_flag, msg, use_file) < 0)
          exit(1);

     /* Release storage space for OID, if still allocated  */
     if (g_mechOid != GSS_C_NULL_OID)
         (void) gss_release_oid(&min_stat, &gmechOid);
         
     return 0;
}