File: /usr/src/linux/fs/hpfs/map.c
1 /*
2 * linux/fs/hpfs/map.c
3 *
4 * Mikulas Patocka (mikulas@artax.karlin.mff.cuni.cz), 1998-1999
5 *
6 * mapping structures to memory with some minimal checks
7 */
8
9 #include "hpfs_fn.h"
10
11 unsigned *hpfs_map_dnode_bitmap(struct super_block *s, struct quad_buffer_head *qbh)
12 {
13 return hpfs_map_4sectors(s, s->s_hpfs_dmap, qbh, 0);
14 }
15
16 unsigned int *hpfs_map_bitmap(struct super_block *s, unsigned bmp_block,
17 struct quad_buffer_head *qbh, char *id)
18 {
19 secno sec;
20 if (s->s_hpfs_chk) if (bmp_block * 16384 > s->s_hpfs_fs_size) {
21 hpfs_error(s, "hpfs_map_bitmap called with bad parameter: %08x at %s", bmp_block, id);
22 return NULL;
23 }
24 sec = s->s_hpfs_bmp_dir[bmp_block];
25 if (!sec || sec > s->s_hpfs_fs_size-4) {
26 hpfs_error(s, "invalid bitmap block pointer %08x -> %08x at %s", bmp_block, sec, id);
27 return NULL;
28 }
29 return hpfs_map_4sectors(s, sec, qbh, 4);
30 }
31
32 /*
33 * Load first code page into kernel memory, return pointer to 256-byte array,
34 * first 128 bytes are uppercasing table for chars 128-255, next 128 bytes are
35 * lowercasing table
36 */
37
38 char *hpfs_load_code_page(struct super_block *s, secno cps)
39 {
40 struct buffer_head *bh;
41 secno cpds;
42 unsigned cpi;
43 unsigned char *ptr;
44 unsigned char *cp_table;
45 int i;
46 struct code_page_data *cpd;
47 struct code_page_directory *cp = hpfs_map_sector(s, cps, &bh, 0);
48 if (!cp) return NULL;
49 if (cp->magic != CP_DIR_MAGIC) {
50 printk("HPFS: Code page directory magic doesn't match (magic = %08x)\n", cp->magic);
51 brelse(bh);
52 return NULL;
53 }
54 if (!cp->n_code_pages) {
55 printk("HPFS: n_code_pages == 0\n");
56 brelse(bh);
57 return NULL;
58 }
59 cpds = cp->array[0].code_page_data;
60 cpi = cp->array[0].index;
61 brelse(bh);
62
63 if (cpi >= 3) {
64 printk("HPFS: Code page index out of array\n");
65 return NULL;
66 }
67
68 if (!(cpd = hpfs_map_sector(s, cpds, &bh, 0))) return NULL;
69 if ((unsigned)cpd->offs[cpi] > 0x178) {
70 printk("HPFS: Code page index out of sector\n");
71 brelse(bh);
72 return NULL;
73 }
74 ptr = (char *)cpd + cpd->offs[cpi] + 6;
75 if (!(cp_table = kmalloc(256, GFP_KERNEL))) {
76 printk("HPFS: out of memory for code page table\n");
77 brelse(bh);
78 return NULL;
79 }
80 memcpy(cp_table, ptr, 128);
81 brelse(bh);
82
83 /* Try to build lowercasing table from uppercasing one */
84
85 for (i=128; i<256; i++) cp_table[i]=i;
86 for (i=128; i<256; i++) if (cp_table[i-128]!=i && cp_table[i-128]>=128)
87 cp_table[cp_table[i-128]] = i;
88
89 return cp_table;
90 }
91
92 secno *hpfs_load_bitmap_directory(struct super_block *s, secno bmp)
93 {
94 struct buffer_head *bh;
95 int n = (s->s_hpfs_fs_size + 0x200000 - 1) >> 21;
96 int i;
97 secno *b;
98 if (!(b = kmalloc(n * 512, GFP_KERNEL))) {
99 printk("HPFS: can't allocate memory for bitmap directory\n");
100 return NULL;
101 }
102 for (i=0;i<n;i++) {
103 secno *d = hpfs_map_sector(s, bmp+i, &bh, n - i - 1);
104 if (!d) {
105 kfree(b);
106 return NULL;
107 }
108 memcpy((char *)b + 512 * i, d, 512);
109 brelse(bh);
110 }
111 return b;
112 }
113
114 /*
115 * Load fnode to memory
116 */
117
118 struct fnode *hpfs_map_fnode(struct super_block *s, ino_t ino, struct buffer_head **bhp)
119 {
120 struct fnode *fnode;
121 if (s->s_hpfs_chk) if (hpfs_chk_sectors(s, ino, 1, "fnode")) {
122 return NULL;
123 }
124 if ((fnode = hpfs_map_sector(s, ino, bhp, FNODE_RD_AHEAD))) {
125 if (s->s_hpfs_chk) {
126 struct extended_attribute *ea;
127 struct extended_attribute *ea_end;
128 if (fnode->magic != FNODE_MAGIC) {
129 hpfs_error(s, "bad magic on fnode %08x", ino);
130 goto bail;
131 }
132 if (!fnode->dirflag) {
133 if ((unsigned)fnode->btree.n_used_nodes + (unsigned)fnode->btree.n_free_nodes !=
134 (fnode->btree.internal ? 12 : 8)) {
135 hpfs_error(s, "bad number of nodes in fnode %08x", ino);
136 goto bail;
137 }
138 if (fnode->btree.first_free !=
139 8 + fnode->btree.n_used_nodes * (fnode->btree.internal ? 8 : 12)) {
140 hpfs_error(s, "bad first_free pointer in fnode %08x", ino);
141 goto bail;
142 }
143 }
144 if (fnode->ea_size_s && ((signed int)fnode->ea_offs < 0xc4 ||
145 (signed int)fnode->ea_offs + fnode->ea_size_s > 0x200)) {
146 hpfs_error(s, "bad EA info in fnode %08x: ea_offs == %04x ea_size_s == %04x",
147 ino, fnode->ea_offs, fnode->ea_size_s);
148 goto bail;
149 }
150 ea = fnode_ea(fnode);
151 ea_end = fnode_end_ea(fnode);
152 while (ea != ea_end) {
153 if (ea > ea_end) {
154 hpfs_error(s, "bad EA in fnode %08x", ino);
155 goto bail;
156 }
157 ea = next_ea(ea);
158 }
159 }
160 }
161 return fnode;
162 bail:
163 brelse(*bhp);
164 return NULL;
165 }
166
167 struct anode *hpfs_map_anode(struct super_block *s, anode_secno ano, struct buffer_head **bhp)
168 {
169 struct anode *anode;
170 if (s->s_hpfs_chk) if (hpfs_chk_sectors(s, ano, 1, "anode")) return NULL;
171 if ((anode = hpfs_map_sector(s, ano, bhp, ANODE_RD_AHEAD)))
172 if (s->s_hpfs_chk) {
173 if (anode->magic != ANODE_MAGIC || anode->self != ano) {
174 hpfs_error(s, "bad magic on anode %08x", ano);
175 goto bail;
176 }
177 if ((unsigned)anode->btree.n_used_nodes + (unsigned)anode->btree.n_free_nodes !=
178 (anode->btree.internal ? 60 : 40)) {
179 hpfs_error(s, "bad number of nodes in anode %08x", ano);
180 goto bail;
181 }
182 if (anode->btree.first_free !=
183 8 + anode->btree.n_used_nodes * (anode->btree.internal ? 8 : 12)) {
184 hpfs_error(s, "bad first_free pointer in anode %08x", ano);
185 goto bail;
186 }
187 }
188 return anode;
189 bail:
190 brelse(*bhp);
191 return NULL;
192 }
193
194 /*
195 * Load dnode to memory and do some checks
196 */
197
198 struct dnode *hpfs_map_dnode(struct super_block *s, unsigned secno,
199 struct quad_buffer_head *qbh)
200 {
201 struct dnode *dnode;
202 if (s->s_hpfs_chk) {
203 if (hpfs_chk_sectors(s, secno, 4, "dnode")) return NULL;
204 if (secno & 3) {
205 hpfs_error(s, "dnode %08x not byte-aligned", secno);
206 return NULL;
207 }
208 }
209 if ((dnode = hpfs_map_4sectors(s, secno, qbh, DNODE_RD_AHEAD)))
210 if (s->s_hpfs_chk) {
211 unsigned p, pp = 0;
212 unsigned char *d = (char *)dnode;
213 int b = 0;
214 if (dnode->magic != DNODE_MAGIC) {
215 hpfs_error(s, "bad magic on dnode %08x", secno);
216 goto bail;
217 }
218 if (dnode->self != secno)
219 hpfs_error(s, "bad self pointer on dnode %08x self = %08x", secno, dnode->self);
220 /* Check dirents - bad dirents would cause infinite
221 loops or shooting to memory */
222 if (dnode->first_free > 2048/* || dnode->first_free < 84*/) {
223 hpfs_error(s, "dnode %08x has first_free == %08x", secno, dnode->first_free);
224 goto bail;
225 }
226 for (p = 20; p < dnode->first_free; p += d[p] + (d[p+1] << 8)) {
227 struct hpfs_dirent *de = (struct hpfs_dirent *)((char *)dnode + p);
228 if (de->length > 292 || (de->length < 32) || (de->length & 3)) {
229 hpfs_error(s, "bad dirent size in dnode %08x, dirent %03x, last %03x", secno, p, pp);
230 goto bail;
231 }
232 if (((31 + de->namelen + de->down*4 + 3) & ~3) != de->length) {
233 hpfs_error(s, "namelen does not match dirent size in dnode %08x, dirent %03x, last %03x", secno, p, pp);
234 goto bail;
235 }
236 if (s->s_hpfs_chk >= 2) b |= 1 << de->down;
237 if (de->down) if (de_down_pointer(de) < 0x10) {
238 hpfs_error(s, "bad down pointer in dnode %08x, dirent %03x, last %03x", secno, p, pp);
239 goto bail;
240 }
241 pp = p;
242
243 }
244 if (p != dnode->first_free) {
245 hpfs_error(s, "size on last dirent does not match first_free; dnode %08x", secno);
246 goto bail;
247 }
248 if (d[pp + 30] != 1 || d[pp + 31] != 255) {
249 hpfs_error(s, "dnode %08x does not end with \\377 entry", secno);
250 goto bail;
251 }
252 if (b == 3) printk("HPFS: warning: unbalanced dnode tree, dnode %08x; see hpfs.txt 4 more info\n", secno);
253 }
254 return dnode;
255 bail:
256 hpfs_brelse4(qbh);
257 return NULL;
258 }
259
260 dnode_secno hpfs_fnode_dno(struct super_block *s, ino_t ino)
261 {
262 struct buffer_head *bh;
263 struct fnode *fnode;
264 dnode_secno dno;
265
266 fnode = hpfs_map_fnode(s, ino, &bh);
267 if (!fnode)
268 return 0;
269
270 dno = fnode->u.external[0].disk_secno;
271 brelse(bh);
272 return dno;
273 }
274