fs/partitions/ldm.c: fix oops caused by corrupted partition table
[linux-2.6.git] / fs / partitions / ultrix.c
1 /*
2  *  fs/partitions/ultrix.c
3  *
4  *  Code extracted from drivers/block/genhd.c
5  *
6  *  Re-organised Jul 1999 Russell King
7  */
8
9 #include "check.h"
10 #include "ultrix.h"
11
12 int ultrix_partition(struct parsed_partitions *state)
13 {
14         int i;
15         Sector sect;
16         unsigned char *data;
17         struct ultrix_disklabel {
18                 s32     pt_magic;       /* magic no. indicating part. info exits */
19                 s32     pt_valid;       /* set by driver if pt is current */
20                 struct  pt_info {
21                         s32             pi_nblocks; /* no. of sectors */
22                         u32             pi_blkoff;  /* block offset for start */
23                 } pt_part[8];
24         } *label;
25
26 #define PT_MAGIC        0x032957        /* Partition magic number */
27 #define PT_VALID        1               /* Indicates if struct is valid */
28
29         data = read_part_sector(state, (16384 - sizeof(*label))/512, &sect);
30         if (!data)
31                 return -1;
32         
33         label = (struct ultrix_disklabel *)(data + 512 - sizeof(*label));
34
35         if (label->pt_magic == PT_MAGIC && label->pt_valid == PT_VALID) {
36                 for (i=0; i<8; i++)
37                         if (label->pt_part[i].pi_nblocks)
38                                 put_partition(state, i+1, 
39                                               label->pt_part[i].pi_blkoff,
40                                               label->pt_part[i].pi_nblocks);
41                 put_dev_sector(sect);
42                 strlcat(state->pp_buf, "\n", PAGE_SIZE);
43                 return 1;
44         } else {
45                 put_dev_sector(sect);
46                 return 0;
47         }
48 }