fs/partitions/ldm.c: fix oops caused by corrupted partition table
[linux-2.6.git] / fs / partitions / atari.c
1 /*
2  *  fs/partitions/atari.c
3  *
4  *  Code extracted from drivers/block/genhd.c
5  *
6  *  Copyright (C) 1991-1998  Linus Torvalds
7  *  Re-organised Feb 1998 Russell King
8  */
9
10 #include <linux/ctype.h>
11 #include "check.h"
12 #include "atari.h"
13
14 /* ++guenther: this should be settable by the user ("make config")?.
15  */
16 #define ICD_PARTS
17
18 /* check if a partition entry looks valid -- Atari format is assumed if at
19    least one of the primary entries is ok this way */
20 #define VALID_PARTITION(pi,hdsiz)                                            \
21     (((pi)->flg & 1) &&                                                      \
22      isalnum((pi)->id[0]) && isalnum((pi)->id[1]) && isalnum((pi)->id[2]) && \
23      be32_to_cpu((pi)->st) <= (hdsiz) &&                                     \
24      be32_to_cpu((pi)->st) + be32_to_cpu((pi)->siz) <= (hdsiz))
25
26 static inline int OK_id(char *s)
27 {
28         return  memcmp (s, "GEM", 3) == 0 || memcmp (s, "BGM", 3) == 0 ||
29                 memcmp (s, "LNX", 3) == 0 || memcmp (s, "SWP", 3) == 0 ||
30                 memcmp (s, "RAW", 3) == 0 ;
31 }
32
33 int atari_partition(struct parsed_partitions *state)
34 {
35         Sector sect;
36         struct rootsector *rs;
37         struct partition_info *pi;
38         u32 extensect;
39         u32 hd_size;
40         int slot;
41 #ifdef ICD_PARTS
42         int part_fmt = 0; /* 0:unknown, 1:AHDI, 2:ICD/Supra */
43 #endif
44
45         rs = read_part_sector(state, 0, &sect);
46         if (!rs)
47                 return -1;
48
49         /* Verify this is an Atari rootsector: */
50         hd_size = state->bdev->bd_inode->i_size >> 9;
51         if (!VALID_PARTITION(&rs->part[0], hd_size) &&
52             !VALID_PARTITION(&rs->part[1], hd_size) &&
53             !VALID_PARTITION(&rs->part[2], hd_size) &&
54             !VALID_PARTITION(&rs->part[3], hd_size)) {
55                 /*
56                  * if there's no valid primary partition, assume that no Atari
57                  * format partition table (there's no reliable magic or the like
58                  * :-()
59                  */
60                 put_dev_sector(sect);
61                 return 0;
62         }
63
64         pi = &rs->part[0];
65         strlcat(state->pp_buf, " AHDI", PAGE_SIZE);
66         for (slot = 1; pi < &rs->part[4] && slot < state->limit; slot++, pi++) {
67                 struct rootsector *xrs;
68                 Sector sect2;
69                 ulong partsect;
70
71                 if ( !(pi->flg & 1) )
72                         continue;
73                 /* active partition */
74                 if (memcmp (pi->id, "XGM", 3) != 0) {
75                         /* we don't care about other id's */
76                         put_partition (state, slot, be32_to_cpu(pi->st),
77                                         be32_to_cpu(pi->siz));
78                         continue;
79                 }
80                 /* extension partition */
81 #ifdef ICD_PARTS
82                 part_fmt = 1;
83 #endif
84                 strlcat(state->pp_buf, " XGM<", PAGE_SIZE);
85                 partsect = extensect = be32_to_cpu(pi->st);
86                 while (1) {
87                         xrs = read_part_sector(state, partsect, &sect2);
88                         if (!xrs) {
89                                 printk (" block %ld read failed\n", partsect);
90                                 put_dev_sector(sect);
91                                 return -1;
92                         }
93
94                         /* ++roman: sanity check: bit 0 of flg field must be set */
95                         if (!(xrs->part[0].flg & 1)) {
96                                 printk( "\nFirst sub-partition in extended partition is not valid!\n" );
97                                 put_dev_sector(sect2);
98                                 break;
99                         }
100
101                         put_partition(state, slot,
102                                    partsect + be32_to_cpu(xrs->part[0].st),
103                                    be32_to_cpu(xrs->part[0].siz));
104
105                         if (!(xrs->part[1].flg & 1)) {
106                                 /* end of linked partition list */
107                                 put_dev_sector(sect2);
108                                 break;
109                         }
110                         if (memcmp( xrs->part[1].id, "XGM", 3 ) != 0) {
111                                 printk("\nID of extended partition is not XGM!\n");
112                                 put_dev_sector(sect2);
113                                 break;
114                         }
115
116                         partsect = be32_to_cpu(xrs->part[1].st) + extensect;
117                         put_dev_sector(sect2);
118                         if (++slot == state->limit) {
119                                 printk( "\nMaximum number of partitions reached!\n" );
120                                 break;
121                         }
122                 }
123                 strlcat(state->pp_buf, " >", PAGE_SIZE);
124         }
125 #ifdef ICD_PARTS
126         if ( part_fmt!=1 ) { /* no extended partitions -> test ICD-format */
127                 pi = &rs->icdpart[0];
128                 /* sanity check: no ICD format if first partition invalid */
129                 if (OK_id(pi->id)) {
130                         strlcat(state->pp_buf, " ICD<", PAGE_SIZE);
131                         for (; pi < &rs->icdpart[8] && slot < state->limit; slot++, pi++) {
132                                 /* accept only GEM,BGM,RAW,LNX,SWP partitions */
133                                 if (!((pi->flg & 1) && OK_id(pi->id)))
134                                         continue;
135                                 part_fmt = 2;
136                                 put_partition (state, slot,
137                                                 be32_to_cpu(pi->st),
138                                                 be32_to_cpu(pi->siz));
139                         }
140                         strlcat(state->pp_buf, " >", PAGE_SIZE);
141                 }
142         }
143 #endif
144         put_dev_sector(sect);
145
146         strlcat(state->pp_buf, "\n", PAGE_SIZE);
147
148         return 1;
149 }