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bpc_poolWrite.c  view on Meta::CPAN

/*
 * Routines for matching and writing files in the pool.
 *
 * Copyright (C) 2013 Craig Barratt.
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 3 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License along
 * with this program; if not, visit the http://fsf.org website.
 */

#include "backuppc.h"


static uint32 PoolWriteCnt = 0;

/*
 * Buffer used in various places for copying, comparing etc
 */
#define COMPARE_BUF_SZ     (1 << 20)     /* 1.0 MB */
static uchar TempBuf[2 * COMPARE_BUF_SZ];

/*
 * A freelist of unused BPC_POOL_WRITE_BUF_SZ sized-buffers.
 * We use the first sizeof(void*) bytes of the buffer as a single-linked
 * list, with a NULL at the end.
 */
static void *DataBufferFreeList = (void*)NULL;

int bpc_poolWrite_open(bpc_poolWrite_info *info, int compress, bpc_digest *digest)
{
    int i;

    info->compress      = compress;
    info->eof           = 0;
    info->errorCnt      = 0;
    info->state         = 0;
    info->bufferIdx     = 0;
    info->fileSize      = 0;
    info->matchPosn     = 0;
    info->candidateList = NULL;
    info->fdOpen        = 0;
    info->retValue      = -1;
    info->poolFileSize  = 0;
    info->retryCnt      = 0;
    info->digestExtOpen = -1;
    info->digestExtZeroLen = -1;
    for ( i = 0 ; i < BPC_POOL_WRITE_CONCURRENT_MATCH ; i++ ) {
        info->match[i].used = 0;
    }
    if ( DataBufferFreeList ) {
        info->buffer = DataBufferFreeList;
        DataBufferFreeList = *(void**)DataBufferFreeList;
    } else {
        info->buffer = malloc(BPC_POOL_WRITE_BUF_SZ);
    }
    if ( !info->buffer ) {
        bpc_logErrf("bpc_poolWrite_open: can't allocate %d bytes for buffer\n", BPC_POOL_WRITE_BUF_SZ);
        return -1;
    }
    if ( digest ) {
        info->digest = *digest;
        /* TODO: don't have V3 digest at this point! */
        info->state = 2;
    } else {
        info->digest.len = 0;
    }
    info->digest_v3.len = 0;
    if ( snprintf(info->tmpFileName, sizeof(info->tmpFileName), "%s/%d.%d.%d",
                compress ? BPC_CPoolDir : BPC_PoolDir, (int)getpid(), PoolWriteCnt++,
                BPC_TmpFileUnique >= 0 ? BPC_TmpFileUnique : 0) >= (int)sizeof(info->tmpFileName) - 1 ) {
        bpc_logErrf("bpc_poolWrite_open: file name too long %s\n", info->tmpFileName);