Example B-1 Using OCI to Externalize SYS_CONTEXT with OLS

#ifdef RCSID
static char *RCSid =
   "$Header: ext_mls.c 09-may-00.10:07:08 jdoe Exp $ ";
#endif /* RCSID */

/* Copyright (c) Oracle Corporation 1999, 2000. All Rights Reserved. */

/*

   NAME
ext_mls.c - externalized SYS_CONTEXT with Label Security

   DESCRIPTION
Run olsdemo.sql script before executing this example.
Usage: <executable obtained with .c file> <user_name> <password> <session-initial-label
Example: avg_sal sa_demo sa_demo L3:M,E:D10

   PUBLIC FUNCTION(S)
<list of external functions declared/defined - with one-line descriptions>

   PRIVATE FUNCTION(S)
<list of static functions defined in .c file - with one-line descriptions>

   RETURNS
The average salary in the EMP table of the SA_DEMO schema querying as the specified user with the specified session label.

   NOTES
<other useful comments, qualifications, and so on>

   MODIFIED   (MM/DD/YY)
jlev      09/18/03 - cleanup
jdoe      05/09/00 - cleanup
   jdoe      10/13/99 - standalone OCI program to test MLS SYS_CONTEXT
   jdoe      10/13/99 - Creation

*/
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <oci.h>

static OCIEnv *envhp;
static OCIError *errhp;

int main(/*_ int argc, char *argv[] _*/);

/* get and print error */
static void checkerr(/*_OCIError *errhp, sword status _*/);
/* print error */
static void printerr(char *call);
static sword status;

/* return the average of employees' salary */
static CONST text *const selectstmt = (text *)
     "select avg(sal) from sa_demo.emp";
 
int main(argc, argv)
int argc;
char *argv[];
{
  OCISession *authp = (OCISession *) 0;
  OCIServer *srvhp;
  OCISvcCtx *svchp;
  OCIDefine *defnp = (OCIDefine *) 0;
  dvoid *parmdp;
  ub4 ctxsize;
  OCIParam *ctxldesc;
  OCIParam *ctxedesc;
  OCIStmt *stmtp = (OCIStmt *) 0;
  ub4 avg_sal = 0;
  sword status;

  if (OCIInitialize((ub4) OCI_DEFAULT, (dvoid *) 0,
                    (dvoid * (*)(dvoid *, size_t)) 0,
                    (dvoid * (*)(dvoid *, dvoid *, size_t)) 0,
                    (void (*)(dvoid *, dvoid *)) 0))
    printerr("OCIInitialize");

  if (OCIEnvInit((OCIEnv **) &envhp, OCI_DEFAULT, (size_t) 0, (dvoid **) 0))
    printerr("OCIEnvInit");
  
  if (OCIHandleAlloc((dvoid *) envhp, (dvoid **) &errhp, OCI_HTYPE_ERROR,
                     (size_t) 0, (dvoid **) 0))
    printerr("OCIHandleAlloc:OCI_HTYPE_ERROR");

  if (OCIHandleAlloc((dvoid *) envhp, (dvoid **) &srvhp, OCI_HTYPE_SERVER,
                     (size_t) 0, (dvoid **) 0))
    printerr("OCIHandleAlloc:OCI_HTYPE_SERVER");

  if (OCIHandleAlloc((dvoid *) envhp, (dvoid **) &svchp, OCI_HTYPE_SVCCTX,
                     (size_t) 0, (dvoid **) 0))
    printerr("OCIHandleAlloc:OCI_HTYPE_SVCCTX");

  if (OCIServerAttach(srvhp, errhp, (text *) "", strlen(""), 0))
    printerr("OCIServerAttach");

  /* set attribute server context in the service context */
  if (OCIAttrSet((dvoid *) svchp, OCI_HTYPE_SVCCTX, (dvoid *) srvhp,
                 (ub4) 0, OCI_ATTR_SERVER, (OCIError *) errhp))
    printerr("OCIAttrSet:OCI_HTYPE_SVCCTX");

  if (OCIHandleAlloc((dvoid *) envhp, (dvoid **) &authp,
                     (ub4) OCI_HTYPE_SESSION, (size_t) 0, (dvoid **) 0))
    printerr("OCIHandleAlloc:OCI_HTYPE_SESSION");

  /* set application context to 1 */
  ctxsize = 1;

  /* set up app ctx buffer */
  if (OCIAttrSet((dvoid *) authp, (ub4) OCI_HTYPE_SESSION, (dvoid *) &ctxsize,
                 (ub4) 0, (ub4) OCI_ATTR_APPCTX_SIZE, errhp))
    printerr("OCIAttrSet:OCI_ATTR_APPCTX_SIZE");

  /* retrieve the list descriptor */
  if (OCIAttrGet((dvoid *) authp, (ub4) OCI_HTYPE_SESSION,
                 (dvoid *) &ctxldesc, 0, OCI_ATTR_APPCTX_LIST, errhp))
    printerr("OCIAttrGet:OCI_ATTR_APPCTX_LIST");

  if (status = OCIParamGet(ctxldesc, OCI_DTYPE_PARAM, errhp,
                           (dvoid **) &ctxedesc, 1))
    {
      if (status == OCI_NO_DATA)
        {
          printf("No Data found!\n");
          exit(1);
        }
    }

  /* set context namespace to SA$<pol_name>_X */
  if (OCIAttrSet((dvoid *) ctxedesc, (ub4) OCI_DTYPE_PARAM,
                 (dvoid *) "SA$HUMAN_RESOURCES_X",
                 (ub4) strlen((char *) "SA$HUMAN_RESOURCES_X"),
                 (ub4) OCI_ATTR_APPCTX_NAME, errhp))
    printerr("OCIAttrSet:OCI_ATTR_APPCTX_NAME:SA$HUMAN_RESOURCES_X");

  /* set context attribute to INITIAL_LABEL */
  if (OCIAttrSet((dvoid *) ctxedesc, (ub4) OCI_DTYPE_PARAM,
                 (dvoid *) "INITIAL_LABEL",
                 (ub4) strlen((char *) "INITIAL_LABEL"),
                 (ub4) OCI_ATTR_APPCTX_ATTR, errhp))
    printerr("OCIAttrSet:OCI_DTYPE_PARAM:INITIAL_LABEL");

  /* set context value to argv[3] - initial label */
  if (OCIAttrSet((dvoid *) ctxedesc, (ub4) OCI_DTYPE_PARAM,
                 (dvoid *) argv[3],
                 (ub4) strlen((char *) argv[3]),
                 (ub4) OCI_ATTR_APPCTX_VALUE, errhp))
    printerr("OCIAttrSet:argv[3]");

  /* username first command line argument */
  if (OCIAttrSet((dvoid *) authp, (ub4) OCI_HTYPE_SESSION, (dvoid *) argv[1],
                 (ub4) strlen((char *) argv[1]), (ub4) OCI_ATTR_USERNAME,
                 errhp))
    printerr("OCIAttrSet:username");

  /* password second command line argument */
  if (OCIAttrSet((dvoid *) authp, (ub4) OCI_HTYPE_SESSION, (dvoid *) argv[2],
                 (ub4) strlen((char *) argv[2]), (ub4) OCI_ATTR_PASSWORD,
                 errhp))
    printerr("OCIAttrSet:password");

  if (OCISessionBegin(svchp, errhp, authp, OCI_CRED_RDBMS, (ub4) OCI_DEFAULT))
    printerr("OCISessionBegin");

  if (OCIAttrSet((dvoid *) svchp, (ub4) OCI_HTYPE_SVCCTX, (dvoid *) authp,
                 (ub4) 0, (ub4) OCI_ATTR_SESSION, errhp))
    printerr("OCIAttrSet:OCI_ATTR_SESSION");

  if (OCIHandleAlloc((dvoid *) envhp, (dvoid **) &stmtp, OCI_HTYPE_STMT,
                     0, 0))
    printerr("OCIHandleAlloc:OCI_HTYPE_STMT");

  if (OCIStmtPrepare(stmtp, errhp, (CONST OraText *) selectstmt,
                     (ub4) strlen((const char *) selectstmt),
                     (ub4) OCI_NTV_SYNTAX, (ub4) OCI_DEFAULT))
    printerr("OCIStmtPrepare");

  if (OCIDefineByPos(stmtp, &defnp, errhp, (ub4) 1, (dvoid *) &avg_sal,
                     (sb4) sizeof(avg_sal), SQLT_INT, 0, 0, 0, OCI_DEFAULT))
    printerr("OCIDefineByPos");

  if (status = OCIStmtExecute(svchp, stmtp, errhp, 1, 0, NULL, NULL,
                              OCI_DEFAULT))
    {
      if (status == OCI_NO_DATA)
        {
          printf("No Data found!\n");
          exit(1);
        }
    }

  if (OCISessionEnd(svchp, errhp, authp, OCI_DEFAULT))
    printerr("OCISessionEnd");

  printf("average salary is: %d\n", avg_sal);
}

void checkerr(errhp, status)
     OCIError *errhp;
     sword status;
{
  text errbuf[512];
  sb4 errcode = 0;

  switch (status)
    {
    case OCI_ERROR:
      (void) OCIErrorGet((dvoid *) errhp, 1, NULL, &errcode, errbuf,
                         (ub4) sizeof(errbuf), OCI_HTYPE_ERROR);
      printf("Error - %.*s\n", 512, errbuf);
      break;
    default:
      break;
    }
}

void printerr(call)
     char *call;
{
  printf("Error: %s\n", call);
}
/* end of file ext_mls.c */