xref: /minix3/minix/lib/libc/gen/fslib.c (revision ef9dc93f44157dea667de514ba31c214ccba64cc)
1bad58c9cSBen Gras /* fslib.c - routines needed by fs and fs utilities */
2bad58c9cSBen Gras 
3bad58c9cSBen Gras #include <minix/config.h>	/* for unused stuff in <minix/type.h> :-( */
4bad58c9cSBen Gras #include <limits.h>
5bad58c9cSBen Gras #include <dirent.h>
6bad58c9cSBen Gras #include <assert.h>
720a91f77SLionel Sambuc #include <stdlib.h>		/* for abort() */
8bad58c9cSBen Gras #include <sys/types.h>
9bad58c9cSBen Gras #include <minix/const.h>
10bad58c9cSBen Gras #include <minix/type.h>		/* for unshort :-( */
11bad58c9cSBen Gras #include <minix/minlib.h>
12*ccaeedb2SDavid van Moolenbroek #include <minix/ipc.h>
13bad58c9cSBen Gras #include "mfs/const.h"		/* depends of -I flag in Makefile */
14bad58c9cSBen Gras #include "mfs/type.h"		/* ditto */
15bad58c9cSBen Gras #include "mfs/inode.h"		/* ditto */
16bad58c9cSBen Gras #include "mfs/super.h"
17bad58c9cSBen Gras #include <minix/fslib.h>
18bad58c9cSBen Gras 
19bad58c9cSBen Gras /* The next routine is copied from fsck.c and mkfs.c...  (Re)define some
20bad58c9cSBen Gras  * things for consistency.  Some things should be done better.
21bad58c9cSBen Gras  */
22bad58c9cSBen Gras 
23bad58c9cSBen Gras /* Convert from bit count to a block count. The usual expression
24bad58c9cSBen Gras  *
25bad58c9cSBen Gras  *	(nr_bits + (1 << BITMAPSHIFT) - 1) >> BITMAPSHIFT
26bad58c9cSBen Gras  *
27bad58c9cSBen Gras  * doesn't work because of overflow.
28bad58c9cSBen Gras  *
29bad58c9cSBen Gras  * Other overflow bugs, such as the expression for N_ILIST overflowing when
30bad58c9cSBen Gras  * s_inodes is just over V*_INODES_PER_BLOCK less than the maximum+1, are not
31bad58c9cSBen Gras  * fixed yet, because that number of inodes is silly.
32bad58c9cSBen Gras  */
33bad58c9cSBen Gras /* The above comment doesn't all apply now bit_t is long.  Overflow is now
34bad58c9cSBen Gras  * unlikely, but negative bit counts are now possible (though unlikely)
35bad58c9cSBen Gras  * and give silly results.
36bad58c9cSBen Gras  */
bitmapsize(nr_bits,block_size)37bad58c9cSBen Gras int bitmapsize(nr_bits, block_size)
38bad58c9cSBen Gras bit_t nr_bits;
39bad58c9cSBen Gras int block_size;
40bad58c9cSBen Gras {
41bad58c9cSBen Gras   int nr_blocks;
42bad58c9cSBen Gras 
43bad58c9cSBen Gras   nr_blocks = (int) (nr_bits / FS_BITS_PER_BLOCK(block_size));
44bad58c9cSBen Gras   if (((bit_t) nr_blocks * FS_BITS_PER_BLOCK(block_size)) < nr_bits) ++nr_blocks;
45bad58c9cSBen Gras   return(nr_blocks);
46bad58c9cSBen Gras }
47