Seite 9: Listing 5

Inhaltsverzeichnis

Listing 5: processBlock() ist die Startroutine des Threads

int    processBlock(PBP_S pbp_s) {
    DWORD dwTid;

    /**
     * given is the inputBlock with inputSize bytes length
     * and an outputBlock which is at least allocated with 2 times 
     * of inputSize length the processed outputBlock length will
     * be returned in *outputSize
     */
    int ret, outputSize=2*pbp_s->inputSize;
    uchar *outputBlock=malloc(outputSize);

    if ((ret=compress2(outputBlock, (ulong *)&outputSize, 
        pbp_s->inputBlock, pbp_s->inputSize, 
           Z_BEST_COMPRESSION))!=Z_OK) {
        fprintf(stderr,"compress2() returned %d and failed\n",ret);
        return -1;
    }
    if (isCrypt) {
#ifdef WIN32
        /**
         * to be thread - safe it is necessary to initialize an 
         * own context for each thread
         */
        bool    bResult;
        DWORD    dwSize;
        HCRYPTPROV    hProv;
        HCRYPTHASH    hHash;
        HCRYPTKEY    hKey;

        if (!CryptAcquireContext(&hProv, NULL, MS_DEF_PROV, 
              PROV_RSA_FULL, 0)) {
            fprintf(stderr,"CryptAcquireContext() FAILED!\n");
            return -1;
        }
        if (!CryptCreateHash(hProv, CALG_MD5, 0, 0, &hHash)) {
            fprintf(stderr,"CryptCreateHash() FAILED!\n");
            return -1;
        }
        if (!CryptHashData(hHash, passwd, strlen(passwd), 0)) {
            fprintf(stderr,"CryptHashData() FAILED!\n");
            return -1;
        }
        if (!CryptDeriveKey(hProv, CALG_RC4, hHash, 
               CRYPT_EXPORTABLE, &hKey)) {
            fprintf(stderr,"CryptDeriveKey() FAILED!\n");
            return -1;
        }
        dwSize=outputSize;
        if (!CryptEncrypt(hKey, 0, TRUE, 0, NULL, &dwSize, outputSize)) {
            fprintf(stderr,"CryptEncrypt(1) FAILED!\n");
            return -1;
        }
        if (!CryptEncrypt(hKey, 0, TRUE, 0, outputBlock, &dwSize, dwSize)) {
            fprintf(stderr,"CryptEncrypt(2) FAILED!\n");
            return -1;
        }
        outputSize=dwSize;
        CryptDestroyKey(hKey);
        CryptDestroyHash(hHash);
        CryptReleaseContext(hProv, 0);
#endif
    }
    pbp_s->outputBlock=outputBlock;
    pbp_s->outputSize=outputSize;
    if (CreateThread((LPSECURITY_ATTRIBUTES)NULL,0,
        (LPTHREAD_START_ROUTINE)flushBlockToFile,(LPVOID)pbp_s,0,
            &dwTid)==NULL) {
        fprintf(stderr,"CreateThread(flushBlockToFile()) failed!\n");
        fclose(pbp_s->ofp);
        return -1;
    }
    free(pbp_s->inputBlock);
    WaitForSingleObject(blocksWrittenMutex, INFINITE);
    threadActiveCount--;
    ReleaseMutex(blocksWrittenMutex);
    return 0;
}