mirror of
https://github.com/sheumann/hush.git
synced 2024-11-19 08:31:11 +00:00
80 lines
1.6 KiB
C
80 lines
1.6 KiB
C
/* vi: set sw=4 ts=4: */
|
|
/*
|
|
* sparse.c --- find the groups in an ext2 filesystem with metadata backups
|
|
*
|
|
* Copyright (C) 1993, 1994, 1995, 1996 Theodore Ts'o.
|
|
* Copyright (C) 2002 Andreas Dilger.
|
|
*
|
|
* %Begin-Header%
|
|
* This file may be redistributed under the terms of the GNU Public
|
|
* License.
|
|
* %End-Header%
|
|
*/
|
|
|
|
#include <stdio.h>
|
|
|
|
#include "ext2_fs.h"
|
|
#include "ext2fsP.h"
|
|
|
|
static int test_root(int a, int b)
|
|
{
|
|
if (a == 0)
|
|
return 1;
|
|
while (1) {
|
|
if (a == 1)
|
|
return 1;
|
|
if (a % b)
|
|
return 0;
|
|
a = a / b;
|
|
}
|
|
}
|
|
|
|
int ext2fs_bg_has_super(ext2_filsys fs, int group_block)
|
|
{
|
|
if (!(fs->super->s_feature_ro_compat &
|
|
EXT2_FEATURE_RO_COMPAT_SPARSE_SUPER))
|
|
return 1;
|
|
|
|
if (test_root(group_block, 3) || (test_root(group_block, 5)) ||
|
|
test_root(group_block, 7))
|
|
return 1;
|
|
|
|
return 0;
|
|
}
|
|
|
|
/*
|
|
* Iterate through the groups which hold BACKUP superblock/GDT copies in an
|
|
* ext3 filesystem. The counters should be initialized to 1, 5, and 7 before
|
|
* calling this for the first time. In a sparse filesystem it will be the
|
|
* sequence of powers of 3, 5, and 7: 1, 3, 5, 7, 9, 25, 27, 49, 81, ...
|
|
* For a non-sparse filesystem it will be every group: 1, 2, 3, 4, ...
|
|
*/
|
|
unsigned int ext2fs_list_backups(ext2_filsys fs, unsigned int *three,
|
|
unsigned int *five, unsigned int *seven)
|
|
{
|
|
unsigned int *min = three;
|
|
int mult = 3;
|
|
unsigned int ret;
|
|
|
|
if (!(fs->super->s_feature_ro_compat &
|
|
EXT2_FEATURE_RO_COMPAT_SPARSE_SUPER)) {
|
|
ret = *min;
|
|
*min += 1;
|
|
return ret;
|
|
}
|
|
|
|
if (*five < *min) {
|
|
min = five;
|
|
mult = 5;
|
|
}
|
|
if (*seven < *min) {
|
|
min = seven;
|
|
mult = 7;
|
|
}
|
|
|
|
ret = *min;
|
|
*min *= mult;
|
|
|
|
return ret;
|
|
}
|