isc/unix/pk11_api.c

	pk11_api.c revision 0c27b3fe77ac1d5094ba3521e8142d9e7973133f
/*
 * Copyright (C) 2014, 2016  Internet Systems Consortium, Inc. ("ISC")
 *
 * This Source Code Form is subject to the terms of the Mozilla Public
 * License, v. 2.0. If a copy of the MPL was not distributed with this
 * file, You can obtain one at http://mozilla.org/MPL/2.0/.
 */

/* $Id$ */

/*! \file */

#include <config.h>

#include <string.h>
#include <dlfcn.h>

#include <isc/log.h>
#include <isc/mem.h>
#include <isc/once.h>
#include <isc/stdio.h>
#include <isc/thread.h>
#include <isc/util.h>

#include <pkcs11/cryptoki.h>
#include <pkcs11/pkcs11.h>

#define KEEP_PKCS11_NAMES
#include <pk11/pk11.h>
#include <pk11/internal.h>

static void *hPK11 = NULL;

CK_RV
pkcs_C_Initialize(CK_VOID_PTR pReserved) {
    CK_C_Initialize sym;

    if (hPK11 != NULL)
        return (CKR_LIBRARY_ALREADY_INITIALIZED);

    hPK11 = dlopen(pk11_get_lib_name(), RTLD_NOW);

    if (hPK11 == NULL)
        return (CKR_LIBRARY_FAILED_TO_LOAD);
    sym = (CK_C_Initialize)dlsym(hPK11, "C_Initialize");
    if (sym == NULL)
        return (CKR_SYMBOL_RESOLUTION_FAILED);
    return (*sym)(pReserved);
}

CK_RV
pkcs_C_Finalize(CK_VOID_PTR pReserved) {
    CK_C_Finalize sym;
    CK_RV rv;

    if (hPK11 == NULL)
        return (CKR_LIBRARY_FAILED_TO_LOAD);
    sym = (CK_C_Finalize)dlsym(hPK11, "C_Finalize");
    if (sym == NULL)
        return (CKR_SYMBOL_RESOLUTION_FAILED);
    rv = (*sym)(pReserved);
    if ((rv == CKR_OK) && (dlclose(hPK11) != 0))
        return (CKR_LIBRARY_FAILED_TO_LOAD);
    hPK11 = NULL;
    return (rv);
}

CK_RV
pkcs_C_GetSlotList(CK_BBOOL tokenPresent, CK_SLOT_ID_PTR pSlotList,
           CK_ULONG_PTR pulCount)
{
    static CK_C_GetSlotList sym = NULL;
    static void *pPK11 = NULL;

    if (hPK11 == NULL)
        return (CKR_LIBRARY_FAILED_TO_LOAD);
    if ((sym == NULL) || (hPK11 != pPK11)) {
        pPK11 = hPK11;
        sym = (CK_C_GetSlotList)dlsym(hPK11, "C_GetSlotList");
    }
    if (sym == NULL)
        return (CKR_SYMBOL_RESOLUTION_FAILED);
    return (*sym)(tokenPresent, pSlotList, pulCount);
}

CK_RV
pkcs_C_GetTokenInfo(CK_SLOT_ID slotID, CK_TOKEN_INFO_PTR pInfo) {
    static CK_C_GetTokenInfo sym = NULL;
    static void *pPK11 = NULL;

    if (hPK11 == NULL)
        return (CKR_LIBRARY_FAILED_TO_LOAD);
    if ((sym == NULL) || (hPK11 != pPK11)) {
        pPK11 = hPK11;
        sym = (CK_C_GetTokenInfo)dlsym(hPK11, "C_GetTokenInfo");
    }
    if (sym == NULL)
        return (CKR_SYMBOL_RESOLUTION_FAILED);
    return (*sym)(slotID, pInfo);
}

CK_RV
pkcs_C_GetMechanismInfo(CK_SLOT_ID slotID, CK_MECHANISM_TYPE type,
            CK_MECHANISM_INFO_PTR pInfo)
{
    static CK_C_GetMechanismInfo sym = NULL;
    static void *pPK11 = NULL;

    if (hPK11 == NULL)
        return (CKR_LIBRARY_FAILED_TO_LOAD);
    if ((sym == NULL) || (hPK11 != pPK11)) {
        pPK11 = hPK11;
        sym = (CK_C_GetMechanismInfo)dlsym(hPK11,
                           "C_GetMechanismInfo");
    }
    if (sym == NULL)
        return (CKR_SYMBOL_RESOLUTION_FAILED);
    return (*sym)(slotID, type, pInfo);
}

CK_RV
pkcs_C_OpenSession(CK_SLOT_ID slotID, CK_FLAGS flags,
           CK_VOID_PTR pApplication,
           CK_RV  (*Notify) (CK_SESSION_HANDLE hSession,
                     CK_NOTIFICATION event,
                     CK_VOID_PTR pApplication),
           CK_SESSION_HANDLE_PTR phSession)
{
    static CK_C_OpenSession sym = NULL;
    static void *pPK11 = NULL;

    if (hPK11 == NULL)
        hPK11 = dlopen(pk11_get_lib_name(), RTLD_NOW);
    if (hPK11 == NULL)
        return (CKR_LIBRARY_FAILED_TO_LOAD);
    if ((sym == NULL) || (hPK11 != pPK11)) {
        pPK11 = hPK11;
        sym = (CK_C_OpenSession)dlsym(hPK11, "C_OpenSession");
    }
    if (sym == NULL)
        return (CKR_SYMBOL_RESOLUTION_FAILED);
    return (*sym)(slotID, flags, pApplication, Notify, phSession);
}

CK_RV
pkcs_C_CloseSession(CK_SESSION_HANDLE hSession) {
    static CK_C_CloseSession sym = NULL;
    static void *pPK11 = NULL;

    if (hPK11 == NULL)
        return (CKR_LIBRARY_FAILED_TO_LOAD);
    if ((sym == NULL) || (hPK11 != pPK11)) {
        pPK11 = hPK11;
        sym = (CK_C_CloseSession)dlsym(hPK11, "C_CloseSession");
    }
    if (sym == NULL)
        return (CKR_SYMBOL_RESOLUTION_FAILED);
    return (*sym)(hSession);
}

CK_RV
pkcs_C_Login(CK_SESSION_HANDLE hSession, CK_USER_TYPE userType,
         CK_CHAR_PTR pPin, CK_ULONG usPinLen)
{
    static CK_C_Login sym = NULL;
    static void *pPK11 = NULL;

    if (hPK11 == NULL)
        return (CKR_LIBRARY_FAILED_TO_LOAD);
    if ((sym == NULL) || (hPK11 != pPK11)) {
        pPK11 = hPK11;
        sym = (CK_C_Login)dlsym(hPK11, "C_Login");
    }
    if (sym == NULL)
        return (CKR_SYMBOL_RESOLUTION_FAILED);
    return (*sym)(hSession, userType, pPin, usPinLen);
}

CK_RV
pkcs_C_Logout(CK_SESSION_HANDLE hSession) {
    static CK_C_Logout sym = NULL;
    static void *pPK11 = NULL;

    if (hPK11 == NULL)
        return (CKR_LIBRARY_FAILED_TO_LOAD);
    if ((sym == NULL) || (hPK11 != pPK11)) {
        pPK11 = hPK11;
        sym = (CK_C_Logout)dlsym(hPK11, "C_Logout");
    }
    if (sym == NULL)
        return (CKR_SYMBOL_RESOLUTION_FAILED);
    return (*sym)(hSession);
}

CK_RV
pkcs_C_CreateObject(CK_SESSION_HANDLE hSession, CK_ATTRIBUTE_PTR pTemplate,
            CK_ULONG usCount, CK_OBJECT_HANDLE_PTR phObject)
{
    static CK_C_CreateObject sym = NULL;
    static void *pPK11 = NULL;

    if (hPK11 == NULL)
        return (CKR_LIBRARY_FAILED_TO_LOAD);
    if ((sym == NULL) || (hPK11 != pPK11)) {
        pPK11 = hPK11;
        sym = (CK_C_CreateObject)dlsym(hPK11, "C_CreateObject");
    }
    if (sym == NULL)
        return (CKR_SYMBOL_RESOLUTION_FAILED);
    return (*sym)(hSession, pTemplate, usCount, phObject);
}

CK_RV
pkcs_C_DestroyObject(CK_SESSION_HANDLE hSession, CK_OBJECT_HANDLE hObject) {
    static CK_C_DestroyObject sym = NULL;
    static void *pPK11 = NULL;

    if (hPK11 == NULL)
        return (CKR_LIBRARY_FAILED_TO_LOAD);
    if ((sym == NULL) || (hPK11 != pPK11)) {
        pPK11 = hPK11;
        sym = (CK_C_DestroyObject)dlsym(hPK11, "C_DestroyObject");
    }
    if (sym == NULL)
        return (CKR_SYMBOL_RESOLUTION_FAILED);
    return (*sym)(hSession, hObject);
}

CK_RV
pkcs_C_GetAttributeValue(CK_SESSION_HANDLE hSession, CK_OBJECT_HANDLE hObject,
             CK_ATTRIBUTE_PTR pTemplate, CK_ULONG usCount)
{
    static CK_C_GetAttributeValue sym = NULL;
    static void *pPK11 = NULL;

    if (hPK11 == NULL)
        return (CKR_LIBRARY_FAILED_TO_LOAD);
    if ((sym == NULL) || (hPK11 != pPK11)) {
        pPK11 = hPK11;
        sym = (CK_C_GetAttributeValue)dlsym(hPK11,
                            "C_GetAttributeValue");
    }
    if (sym == NULL)
        return (CKR_SYMBOL_RESOLUTION_FAILED);
    return (*sym)(hSession, hObject, pTemplate, usCount);
}

CK_RV
pkcs_C_SetAttributeValue(CK_SESSION_HANDLE hSession, CK_OBJECT_HANDLE hObject,
             CK_ATTRIBUTE_PTR pTemplate, CK_ULONG usCount)
{
    static CK_C_SetAttributeValue sym = NULL;
    static void *pPK11 = NULL;

    if (hPK11 == NULL)
        return (CKR_LIBRARY_FAILED_TO_LOAD);
    if ((sym == NULL) || (hPK11 != pPK11)) {
        pPK11 = hPK11;
        sym = (CK_C_SetAttributeValue)dlsym(hPK11,
                            "C_SetAttributeValue");
    }
    if (sym == NULL)
        return (CKR_SYMBOL_RESOLUTION_FAILED);
    return (*sym)(hSession, hObject, pTemplate, usCount);
}

CK_RV
pkcs_C_FindObjectsInit(CK_SESSION_HANDLE hSession, CK_ATTRIBUTE_PTR pTemplate,
               CK_ULONG usCount)
{
    static CK_C_FindObjectsInit sym = NULL;
    static void *pPK11 = NULL;

    if (hPK11 == NULL)
        return (CKR_LIBRARY_FAILED_TO_LOAD);
    if ((sym == NULL) || (hPK11 != pPK11)) {
        pPK11 = hPK11;
        sym = (CK_C_FindObjectsInit)dlsym(hPK11, "C_FindObjectsInit");
    }
    if (sym == NULL)
        return (CKR_SYMBOL_RESOLUTION_FAILED);
    return (*sym)(hSession, pTemplate, usCount);
}

CK_RV
pkcs_C_FindObjects(CK_SESSION_HANDLE hSession, CK_OBJECT_HANDLE_PTR phObject,
           CK_ULONG usMaxObjectCount, CK_ULONG_PTR pusObjectCount)
{
    static CK_C_FindObjects sym = NULL;
    static void *pPK11 = NULL;

    if (hPK11 == NULL)
        return (CKR_LIBRARY_FAILED_TO_LOAD);
    if ((sym == NULL) || (hPK11 != pPK11)) {
        pPK11 = hPK11;
        sym = (CK_C_FindObjects)dlsym(hPK11, "C_FindObjects");
    }
    if (sym == NULL)
        return (CKR_SYMBOL_RESOLUTION_FAILED);
    return (*sym)(hSession, phObject, usMaxObjectCount, pusObjectCount);
}

CK_RV
pkcs_C_FindObjectsFinal(CK_SESSION_HANDLE hSession)
{
    static CK_C_FindObjectsFinal sym = NULL;
    static void *pPK11 = NULL;

    if (hPK11 == NULL)
        return (CKR_LIBRARY_FAILED_TO_LOAD);
    if ((sym == NULL) || (hPK11 != pPK11)) {
        pPK11 = hPK11;
        sym = (CK_C_FindObjectsFinal)dlsym(hPK11,
                           "C_FindObjectsFinal");
    }
    if (sym == NULL)
        return (CKR_SYMBOL_RESOLUTION_FAILED);
    return (*sym)(hSession);
}

CK_RV
pkcs_C_EncryptInit(CK_SESSION_HANDLE hSession, CK_MECHANISM_PTR pMechanism,
           CK_OBJECT_HANDLE hKey)
{
    static CK_C_EncryptInit sym = NULL;
    static void *pPK11 = NULL;

    if (hPK11 == NULL)
        return (CKR_LIBRARY_FAILED_TO_LOAD);
    if ((sym == NULL) || (hPK11 != pPK11)) {
        pPK11 = hPK11;
        sym = (CK_C_EncryptInit)dlsym(hPK11, "C_EncryptInit");
    }
    if (sym == NULL)
        return (CKR_SYMBOL_RESOLUTION_FAILED);
    return (*sym)(hSession, pMechanism, hKey);
}

CK_RV
pkcs_C_Encrypt(CK_SESSION_HANDLE hSession, CK_BYTE_PTR pData,
           CK_ULONG ulDataLen, CK_BYTE_PTR pEncryptedData,
           CK_ULONG_PTR pulEncryptedDataLen)
{
    static CK_C_Encrypt sym = NULL;
    static void *pPK11 = NULL;

    if (hPK11 == NULL)
        return (CKR_LIBRARY_FAILED_TO_LOAD);
    if ((sym == NULL) || (hPK11 != pPK11)) {
        pPK11 = hPK11;
        sym = (CK_C_Encrypt)dlsym(hPK11, "C_Encrypt");
    }
    if (sym == NULL)
        return (CKR_SYMBOL_RESOLUTION_FAILED);
    return (*sym)(hSession, pData, ulDataLen,
              pEncryptedData, pulEncryptedDataLen);
}

CK_RV
pkcs_C_DigestInit(CK_SESSION_HANDLE hSession, CK_MECHANISM_PTR pMechanism) {
    static CK_C_DigestInit sym = NULL;
    static void *pPK11 = NULL;

    if (hPK11 == NULL)
        return (CKR_LIBRARY_FAILED_TO_LOAD);
    if ((sym == NULL) || (hPK11 != pPK11)) {
        pPK11 = hPK11;
        sym = (CK_C_DigestInit)dlsym(hPK11, "C_DigestInit");
    }
    if (sym == NULL)
        return (CKR_SYMBOL_RESOLUTION_FAILED);
    return (*sym)(hSession, pMechanism);
}

CK_RV
pkcs_C_DigestUpdate(CK_SESSION_HANDLE hSession, CK_BYTE_PTR pPart,
            CK_ULONG ulPartLen)
{
    static CK_C_DigestUpdate sym = NULL;
    static void *pPK11 = NULL;

    if (hPK11 == NULL)
        return (CKR_LIBRARY_FAILED_TO_LOAD);
    if ((sym == NULL) || (hPK11 != pPK11)) {
        pPK11 = hPK11;
        sym = (CK_C_DigestUpdate)dlsym(hPK11, "C_DigestUpdate");
    }
    if (sym == NULL)
        return (CKR_SYMBOL_RESOLUTION_FAILED);
    return (*sym)(hSession, pPart, ulPartLen);
}

CK_RV
pkcs_C_DigestFinal(CK_SESSION_HANDLE hSession, CK_BYTE_PTR pDigest,
           CK_ULONG_PTR pulDigestLen)
{
    static CK_C_DigestFinal sym = NULL;
    static void *pPK11 = NULL;

    if (hPK11 == NULL)
        return (CKR_LIBRARY_FAILED_TO_LOAD);
    if ((sym == NULL) || (hPK11 != pPK11)) {
        pPK11 = hPK11;
        sym = (CK_C_DigestFinal)dlsym(hPK11, "C_DigestFinal");
    }
    if (sym == NULL)
        return (CKR_SYMBOL_RESOLUTION_FAILED);
    return (*sym)(hSession, pDigest, pulDigestLen);
}

CK_RV
pkcs_C_SignInit(CK_SESSION_HANDLE hSession, CK_MECHANISM_PTR pMechanism,
        CK_OBJECT_HANDLE hKey)
{
    static CK_C_SignInit sym = NULL;
    static void *pPK11 = NULL;

    if (hPK11 == NULL)
        return (CKR_LIBRARY_FAILED_TO_LOAD);
    if ((sym == NULL) || (hPK11 != pPK11)) {
        pPK11 = hPK11;
        sym = (CK_C_SignInit)dlsym(hPK11, "C_SignInit");
    }
    if (sym == NULL)
        return (CKR_SYMBOL_RESOLUTION_FAILED);
    return (*sym)(hSession, pMechanism, hKey);
}

CK_RV
pkcs_C_Sign(CK_SESSION_HANDLE hSession, CK_BYTE_PTR pData,
        CK_ULONG ulDataLen, CK_BYTE_PTR pSignature,
        CK_ULONG_PTR pulSignatureLen)
{
    static CK_C_Sign sym = NULL;
    static void *pPK11 = NULL;

    if (hPK11 == NULL)
        return (CKR_LIBRARY_FAILED_TO_LOAD);
    if ((sym == NULL) || (hPK11 != pPK11)) {
        pPK11 = hPK11;
        sym = (CK_C_Sign)dlsym(hPK11, "C_Sign");
    }
    if (sym == NULL)
        return (CKR_SYMBOL_RESOLUTION_FAILED);
    return (*sym)(hSession, pData, ulDataLen, pSignature, pulSignatureLen);
}

CK_RV
pkcs_C_SignUpdate(CK_SESSION_HANDLE hSession, CK_BYTE_PTR pPart,
          CK_ULONG ulPartLen)
{
    static CK_C_SignUpdate sym = NULL;
    static void *pPK11 = NULL;

    if (hPK11 == NULL)
        return (CKR_LIBRARY_FAILED_TO_LOAD);
    if ((sym == NULL) || (hPK11 != pPK11)) {
        pPK11 = hPK11;
        sym = (CK_C_SignUpdate)dlsym(hPK11, "C_SignUpdate");
    }
    if (sym == NULL)
        return (CKR_SYMBOL_RESOLUTION_FAILED);
    return (*sym)(hSession, pPart, ulPartLen);
}

CK_RV
pkcs_C_SignFinal(CK_SESSION_HANDLE hSession, CK_BYTE_PTR pSignature,
         CK_ULONG_PTR pulSignatureLen)
{
    static CK_C_SignFinal sym = NULL;
    static void *pPK11 = NULL;

    if (hPK11 == NULL)
        return (CKR_LIBRARY_FAILED_TO_LOAD);
    if ((sym == NULL) || (hPK11 != pPK11)) {
        pPK11 = hPK11;
        sym = (CK_C_SignFinal)dlsym(hPK11, "C_SignFinal");
    }
    if (sym == NULL)
        return (CKR_SYMBOL_RESOLUTION_FAILED);
    return (*sym)(hSession, pSignature, pulSignatureLen);
}

CK_RV
pkcs_C_VerifyInit(CK_SESSION_HANDLE hSession, CK_MECHANISM_PTR pMechanism,
          CK_OBJECT_HANDLE hKey)
{
    static CK_C_VerifyInit sym = NULL;
    static void *pPK11 = NULL;

    if (hPK11 == NULL)
        return (CKR_LIBRARY_FAILED_TO_LOAD);
    if ((sym == NULL) || (hPK11 != pPK11)) {
        pPK11 = hPK11;
        sym = (CK_C_VerifyInit)dlsym(hPK11, "C_VerifyInit");
    }
    if (sym == NULL)
        return (CKR_SYMBOL_RESOLUTION_FAILED);
    return (*sym)(hSession, pMechanism, hKey);
}

CK_RV
pkcs_C_Verify(CK_SESSION_HANDLE hSession, CK_BYTE_PTR pData,
          CK_ULONG ulDataLen, CK_BYTE_PTR pSignature,
          CK_ULONG ulSignatureLen)
{
    static CK_C_Verify sym = NULL;
    static void *pPK11 = NULL;

    if (hPK11 == NULL)
        return (CKR_LIBRARY_FAILED_TO_LOAD);
    if ((sym == NULL) || (hPK11 != pPK11)) {
        pPK11 = hPK11;
        sym = (CK_C_Verify)dlsym(hPK11, "C_Verify");
    }
    if (sym == NULL)
        return (CKR_SYMBOL_RESOLUTION_FAILED);
    return (*sym)(hSession, pData, ulDataLen, pSignature, ulSignatureLen);
}

CK_RV
pkcs_C_VerifyUpdate(CK_SESSION_HANDLE hSession, CK_BYTE_PTR pPart,
            CK_ULONG ulPartLen)
{
    static CK_C_VerifyUpdate sym = NULL;
    static void *pPK11 = NULL;

    if (hPK11 == NULL)
        return (CKR_LIBRARY_FAILED_TO_LOAD);
    if ((sym == NULL) || (hPK11 != pPK11)) {
        pPK11 = hPK11;
        sym = (CK_C_VerifyUpdate)dlsym(hPK11, "C_VerifyUpdate");
    }
    if (sym == NULL)
        return (CKR_SYMBOL_RESOLUTION_FAILED);
    return (*sym)(hSession, pPart, ulPartLen);
}

CK_RV
pkcs_C_VerifyFinal(CK_SESSION_HANDLE hSession, CK_BYTE_PTR pSignature,
           CK_ULONG ulSignatureLen)
{
    static CK_C_VerifyFinal sym = NULL;
    static void *pPK11 = NULL;

    if (hPK11 == NULL)
        return (CKR_LIBRARY_FAILED_TO_LOAD);
    if ((sym == NULL) || (hPK11 != pPK11)) {
        pPK11 = hPK11;
        sym = (CK_C_VerifyFinal)dlsym(hPK11, "C_VerifyFinal");
    }
    if (sym == NULL)
        return (CKR_SYMBOL_RESOLUTION_FAILED);
    return (*sym)(hSession, pSignature, ulSignatureLen);
}

CK_RV
pkcs_C_GenerateKey(CK_SESSION_HANDLE hSession, CK_MECHANISM_PTR pMechanism,
           CK_ATTRIBUTE_PTR pTemplate, CK_ULONG ulCount,
           CK_OBJECT_HANDLE_PTR phKey)
{
    static CK_C_GenerateKey sym = NULL;
    static void *pPK11 = NULL;

    if (hPK11 == NULL)
        return (CKR_LIBRARY_FAILED_TO_LOAD);
    if ((sym == NULL) || (hPK11 != pPK11)) {
        pPK11 = hPK11;
        sym = (CK_C_GenerateKey)dlsym(hPK11, "C_GenerateKey");
    }
    if (sym == NULL)
        return (CKR_SYMBOL_RESOLUTION_FAILED);
    return (*sym)(hSession, pMechanism, pTemplate, ulCount, phKey);
}

CK_RV
pkcs_C_GenerateKeyPair(CK_SESSION_HANDLE hSession,
               CK_MECHANISM_PTR pMechanism,
               CK_ATTRIBUTE_PTR pPublicKeyTemplate,
               CK_ULONG usPublicKeyAttributeCount,
               CK_ATTRIBUTE_PTR pPrivateKeyTemplate,
               CK_ULONG usPrivateKeyAttributeCount,
               CK_OBJECT_HANDLE_PTR phPrivateKey,
               CK_OBJECT_HANDLE_PTR phPublicKey)
{
    static CK_C_GenerateKeyPair sym = NULL;
    static void *pPK11 = NULL;

    if (hPK11 == NULL)
        return (CKR_LIBRARY_FAILED_TO_LOAD);
    if ((sym == NULL) || (hPK11 != pPK11)) {
        pPK11 = hPK11;
        sym = (CK_C_GenerateKeyPair)dlsym(hPK11, "C_GenerateKeyPair");
    }
    if (sym == NULL)
        return (CKR_SYMBOL_RESOLUTION_FAILED);
    return (*sym)(hSession,
              pMechanism,
              pPublicKeyTemplate,
              usPublicKeyAttributeCount,
              pPrivateKeyTemplate,
              usPrivateKeyAttributeCount,
              phPrivateKey,
              phPublicKey);
}

CK_RV
pkcs_C_DeriveKey(CK_SESSION_HANDLE hSession, CK_MECHANISM_PTR pMechanism,
         CK_OBJECT_HANDLE hBaseKey, CK_ATTRIBUTE_PTR pTemplate,
         CK_ULONG ulAttributeCount, CK_OBJECT_HANDLE_PTR phKey)
{
    static CK_C_DeriveKey sym = NULL;
    static void *pPK11 = NULL;

    if (hPK11 == NULL)
        return (CKR_LIBRARY_FAILED_TO_LOAD);
    if ((sym == NULL) || (hPK11 != pPK11)) {
        pPK11 = hPK11;
        sym = (CK_C_DeriveKey)dlsym(hPK11, "C_DeriveKey");
    }
    if (sym == NULL)
        return (CKR_SYMBOL_RESOLUTION_FAILED);
    return (*sym)(hSession,
              pMechanism,
              hBaseKey,
              pTemplate,
              ulAttributeCount,
              phKey);
}

CK_RV
pkcs_C_SeedRandom(CK_SESSION_HANDLE hSession, CK_BYTE_PTR pSeed,
          CK_ULONG ulSeedLen)
{
    static CK_C_SeedRandom sym = NULL;
    static void *pPK11 = NULL;

    if (hPK11 == NULL)
        return (CKR_LIBRARY_FAILED_TO_LOAD);
    if ((sym == NULL) || (hPK11 != pPK11)) {
        pPK11 = hPK11;
        sym = (CK_C_SeedRandom)dlsym(hPK11, "C_SeedRandom");
    }
    if (sym == NULL)
        return (CKR_SYMBOL_RESOLUTION_FAILED);
    return (*sym)(hSession, pSeed, ulSeedLen);
}

CK_RV
pkcs_C_GenerateRandom(CK_SESSION_HANDLE hSession, CK_BYTE_PTR RandomData,
              CK_ULONG ulRandomLen)
{
    static CK_C_GenerateRandom sym = NULL;
    static void *pPK11 = NULL;

    if (hPK11 == NULL)
        return (CKR_LIBRARY_FAILED_TO_LOAD);
    if ((sym == NULL) || (hPK11 != pPK11)) {
        pPK11 = hPK11;
        sym = (CK_C_GenerateRandom)dlsym(hPK11, "C_GenerateRandom");
    }
    if (sym == NULL)
        return (CKR_SYMBOL_RESOLUTION_FAILED);
    return (*sym)(hSession, RandomData, ulRandomLen);
}