aboutsummaryrefslogtreecommitdiffstats
path: root/btrfs-crc.c
diff options
context:
space:
mode:
authorJan Schmidt <list.btrfs@jan-o-sch.net>2013-03-21 17:02:40 +0100
committerDavid Sterba <dsterba@suse.cz>2013-04-09 18:43:32 +0200
commit08fecd7658610d8572b04280d6708960a3265a88 (patch)
treea34dff60a13f72fffe7fe763f0182e40ce590960 /btrfs-crc.c
parentb0029a96f2c6a178183602e1ff11d8d3660ee8fb (diff)
downloadbtrfs-progs-08fecd7658610d8572b04280d6708960a3265a88.tar.gz
btrfs-progs-08fecd7658610d8572b04280d6708960a3265a88.tar.xz
btrfs-progs-08fecd7658610d8572b04280d6708960a3265a88.zip
Btrfs-progs: add btrfs-crc tool
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>
Diffstat (limited to 'btrfs-crc.c')
-rw-r--r--btrfs-crc.c89
1 files changed, 89 insertions, 0 deletions
diff --git a/btrfs-crc.c b/btrfs-crc.c
new file mode 100644
index 0000000..6e21a0e
--- /dev/null
+++ b/btrfs-crc.c
@@ -0,0 +1,89 @@
+/*
+ * Copyright (C) 2013 STRATO. All rights reserved.
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public
+ * License v2 as published by the Free Software Foundation.
+ *
+ * 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, write to the
+ * Free Software Foundation, Inc., 59 Temple Place - Suite 330,
+ * Boston, MA 021110-1307, USA.
+ */
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <unistd.h>
+#include "crc32c.h"
+
+void usage(void)
+{
+ printf("usage: btrfs-crc filename\n");
+ printf(" print out the btrfs crc for \"filename\"\n");
+ printf("usage: btrfs-crc filename -c crc [-s seed] [-l length]\n");
+ printf(" brute force search for file names with the given crc\n");
+ printf(" -s seed the random seed (default: random)\n");
+ printf(" -l length the length of the file names (default: 10)\n");
+ exit(1);
+}
+
+int main(int argc, char **argv)
+{
+ char c;
+ unsigned long checksum = 0;
+ char *str;
+ char *buf;
+ int length = 10;
+ int seed = getpid() ^ getppid();
+ int loop = 0;
+ int i;
+
+ while ((c = getopt(argc, argv, "l:c:s:h")) != -1) {
+ switch (c) {
+ case 'l':
+ length = atol(optarg);
+ break;
+ case 'c':
+ checksum = atol(optarg);
+ loop = 1;
+ break;
+ case 's':
+ seed = atol(optarg);
+ break;
+ case 'h':
+ usage();
+ case '?':
+ return 255;
+ }
+ }
+
+ str = argv[optind];
+
+ if (!loop) {
+ if (optind >= argc) {
+ fprintf(stderr, "not enough arguments\n");
+ return 255;
+ }
+ printf("%12u - %s\n", crc32c(~1, str, strlen(str)), str);
+ return 0;
+ }
+
+ buf = malloc(length);
+ if (!buf)
+ return -ENOMEM;
+ srand(seed);
+
+ while (1) {
+ for (i = 0; i < length; i++)
+ buf[i] = rand() % 94 + 33;
+ if (crc32c(~1, buf, length) == checksum)
+ printf("%12lu - %.*s\n", checksum, length, buf);
+ }
+
+ return 0;
+}