mirror of
https://github.com/kdave/btrfs-progs
synced 2024-12-14 18:37:03 +00:00
08fecd7658
This tool can be used to compute btrfs' style crc32c checksums for filenames as done by the kernel. Additionally, there is -c mode to do a brute force search for file names with a given checksum. Signed-off-by: Jan Schmidt <list.btrfs@jan-o-sch.net>
90 lines
2.1 KiB
C
90 lines
2.1 KiB
C
/*
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* Copyright (C) 2013 STRATO. All rights reserved.
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*
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* This program is free software; you can redistribute it and/or
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* modify it under the terms of the GNU General Public
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* License v2 as published by the Free Software Foundation.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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* General Public License for more details.
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*
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* You should have received a copy of the GNU General Public
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* License along with this program; if not, write to the
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* Free Software Foundation, Inc., 59 Temple Place - Suite 330,
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* Boston, MA 021110-1307, USA.
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*/
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#include <stdio.h>
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#include <stdlib.h>
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#include <unistd.h>
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#include "crc32c.h"
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void usage(void)
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{
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printf("usage: btrfs-crc filename\n");
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printf(" print out the btrfs crc for \"filename\"\n");
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printf("usage: btrfs-crc filename -c crc [-s seed] [-l length]\n");
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printf(" brute force search for file names with the given crc\n");
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printf(" -s seed the random seed (default: random)\n");
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printf(" -l length the length of the file names (default: 10)\n");
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exit(1);
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}
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int main(int argc, char **argv)
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{
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char c;
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unsigned long checksum = 0;
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char *str;
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char *buf;
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int length = 10;
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int seed = getpid() ^ getppid();
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int loop = 0;
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int i;
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while ((c = getopt(argc, argv, "l:c:s:h")) != -1) {
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switch (c) {
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case 'l':
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length = atol(optarg);
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break;
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case 'c':
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checksum = atol(optarg);
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loop = 1;
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break;
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case 's':
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seed = atol(optarg);
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break;
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case 'h':
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usage();
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case '?':
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return 255;
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}
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}
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str = argv[optind];
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if (!loop) {
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if (optind >= argc) {
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fprintf(stderr, "not enough arguments\n");
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return 255;
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}
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printf("%12u - %s\n", crc32c(~1, str, strlen(str)), str);
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return 0;
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}
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buf = malloc(length);
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if (!buf)
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return -ENOMEM;
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srand(seed);
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while (1) {
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for (i = 0; i < length; i++)
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buf[i] = rand() % 94 + 33;
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if (crc32c(~1, buf, length) == checksum)
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printf("%12lu - %.*s\n", checksum, length, buf);
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}
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return 0;
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}
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