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 __le32 *hpfs_map_dnode_bitmap(struct super_block *s, struct quad_buffer_head *qbh)
  12 {
  13         return hpfs_map_4sectors(s, hpfs_sb(s)->sb_dmap, qbh, 0);
  14 }
  15
  16 __le32 *hpfs_map_bitmap(struct super_block *s, unsigned bmp_block,
  17                          struct quad_buffer_head *qbh, char *id)
  18 {
  19         secno sec;
  20         __le32 *ret;
  21         unsigned n_bands = (hpfs_sb(s)->sb_fs_size + 0x3fff) >> 14;
  22         if (hpfs_sb(s)->sb_chk) if (bmp_block >= n_bands) {
  23                 hpfs_error(s, "hpfs_map_bitmap called with bad parameter: %08x at %s", bmp_block, id);
  24                 return NULL;
  25         }
  26         sec = le32_to_cpu(hpfs_sb(s)->sb_bmp_dir[bmp_block]);
  27         if (!sec || sec > hpfs_sb(s)->sb_fs_size-4) {
  28                 hpfs_error(s, "invalid bitmap block pointer %08x -> %08x at %s", bmp_block, sec, id);
  29                 return NULL;
  30         }
  31         ret = hpfs_map_4sectors(s, sec, qbh, 4);
  32         if (ret) hpfs_prefetch_bitmap(s, bmp_block + 1);
  33         return ret;
  34 }
  35
  36 void hpfs_prefetch_bitmap(struct super_block *s, unsigned bmp_block)
  37 {
  38         unsigned to_prefetch, next_prefetch;
  39         unsigned n_bands = (hpfs_sb(s)->sb_fs_size + 0x3fff) >> 14;
  40         if (unlikely(bmp_block >= n_bands))
  41                 return;
  42         to_prefetch = le32_to_cpu(hpfs_sb(s)->sb_bmp_dir[bmp_block]);
  43         if (unlikely(bmp_block + 1 >= n_bands))
  44                 next_prefetch = 0;
  45         else
  46                 next_prefetch = le32_to_cpu(hpfs_sb(s)->sb_bmp_dir[bmp_block + 1]);
  47         hpfs_prefetch_sectors(s, to_prefetch, 4 + 4 * (to_prefetch + 4 == next_prefetch));
  48 }
  49
  50 /*
  51  * Load first code page into kernel memory, return pointer to 256-byte array,
  52  * first 128 bytes are uppercasing table for chars 128-255, next 128 bytes are
  53  * lowercasing table
  54  */
  55
  56 unsigned char *hpfs_load_code_page(struct super_block *s, secno cps)
  57 {
  58         struct buffer_head *bh;
  59         secno cpds;
  60         unsigned cpi;
  61         unsigned char *ptr;
  62         unsigned char *cp_table;
  63         int i;
  64         struct code_page_data *cpd;
  65         struct code_page_directory *cp = hpfs_map_sector(s, cps, &bh, 0);
  66         if (!cp) return NULL;
  67         if (le32_to_cpu(cp->magic) != CP_DIR_MAGIC) {
  68                 printk("HPFS: Code page directory magic doesn't match (magic = %08x)\n", le32_to_cpu(cp->magic));
  69                 brelse(bh);
  70                 return NULL;
  71         }
  72         if (!le32_to_cpu(cp->n_code_pages)) {
  73                 printk("HPFS: n_code_pages == 0\n");
  74                 brelse(bh);
  75                 return NULL;
  76         }
  77         cpds = le32_to_cpu(cp->array[0].code_page_data);
  78         cpi = le16_to_cpu(cp->array[0].index);
  79         brelse(bh);
  80
  81         if (cpi >= 3) {
  82                 printk("HPFS: Code page index out of array\n");
  83                 return NULL;
  84         }
  85
  86         if (!(cpd = hpfs_map_sector(s, cpds, &bh, 0))) return NULL;
  87         if (le16_to_cpu(cpd->offs[cpi]) > 0x178) {
  88                 printk("HPFS: Code page index out of sector\n");
  89                 brelse(bh);
  90                 return NULL;
  91         }
  92         ptr = (unsigned char *)cpd + le16_to_cpu(cpd->offs[cpi]) + 6;
  93         if (!(cp_table = kmalloc(256, GFP_KERNEL))) {
  94                 printk("HPFS: out of memory for code page table\n");
  95                 brelse(bh);
  96                 return NULL;
  97         }
  98         memcpy(cp_table, ptr, 128);
  99         brelse(bh);
 100
 101         /* Try to build lowercasing table from uppercasing one */
 102
 103         for (i=128; i<256; i++) cp_table[i]=i;
 104         for (i=128; i<256; i++) if (cp_table[i-128]!=i && cp_table[i-128]>=128)
 105                 cp_table[cp_table[i-128]] = i;
 106
 107         return cp_table;
 108 }
 109
 110 __le32 *hpfs_load_bitmap_directory(struct super_block *s, secno bmp)
 111 {
 112         struct buffer_head *bh;
 113         int n = (hpfs_sb(s)->sb_fs_size + 0x200000 - 1) >> 21;
 114         int i;
 115         __le32 *b;
 116         if (!(b = kmalloc(n * 512, GFP_KERNEL))) {
 117                 printk("HPFS: can't allocate memory for bitmap directory\n");
 118                 return NULL;
 119         }
 120         for (i=0;i<n;i++) {
 121                 __le32 *d = hpfs_map_sector(s, bmp+i, &bh, n - i - 1);
 122                 if (!d) {
 123                         kfree(b);
 124                         return NULL;
 125                 }
 126                 memcpy((char *)b + 512 * i, d, 512);
 127                 brelse(bh);
 128         }
 129         return b;
 130 }
 131
 132 /*
 133  * Load fnode to memory
 134  */
 135
 136 struct fnode *hpfs_map_fnode(struct super_block *s, ino_t ino, struct buffer_head **bhp)
 137 {
 138         struct fnode *fnode;
 139         if (hpfs_sb(s)->sb_chk) if (hpfs_chk_sectors(s, ino, 1, "fnode")) {
 140                 return NULL;
 141         }
 142         if ((fnode = hpfs_map_sector(s, ino, bhp, FNODE_RD_AHEAD))) {
 143                 if (hpfs_sb(s)->sb_chk) {
 144                         struct extended_attribute *ea;
 145                         struct extended_attribute *ea_end;
 146                         if (le32_to_cpu(fnode->magic) != FNODE_MAGIC) {
 147                                 hpfs_error(s, "bad magic on fnode %08lx",
 148                                         (unsigned long)ino);
 149                                 goto bail;
 150                         }
 151                         if (!fnode_is_dir(fnode)) {
 152                                 if ((unsigned)fnode->btree.n_used_nodes + (unsigned)fnode->btree.n_free_nodes !=
 153                                     (bp_internal(&fnode->btree) ? 12 : 8)) {
 154                                         hpfs_error(s,
 155                                            "bad number of nodes in fnode %08lx",
 156                                             (unsigned long)ino);
 157                                         goto bail;
 158                                 }
 159                                 if (le16_to_cpu(fnode->btree.first_free) !=
 160                                     8 + fnode->btree.n_used_nodes * (bp_internal(&fnode->btree) ? 8 : 12)) {
 161                                         hpfs_error(s,
 162                                             "bad first_free pointer in fnode %08lx",
 163                                             (unsigned long)ino);
 164                                         goto bail;
 165                                 }
 166                         }
 167                         if (le16_to_cpu(fnode->ea_size_s) && (le16_to_cpu(fnode->ea_offs) < 0xc4 ||
 168                            le16_to_cpu(fnode->ea_offs) + le16_to_cpu(fnode->acl_size_s) + le16_to_cpu(fnode->ea_size_s) > 0x200)) {
 169                                 hpfs_error(s,
 170                                         "bad EA info in fnode %08lx: ea_offs == %04x ea_size_s == %04x",
 171                                         (unsigned long)ino,
 172                                         le16_to_cpu(fnode->ea_offs), le16_to_cpu(fnode->ea_size_s));
 173                                 goto bail;
 174                         }
 175                         ea = fnode_ea(fnode);
 176                         ea_end = fnode_end_ea(fnode);
 177                         while (ea != ea_end) {
 178                                 if (ea > ea_end) {
 179                                         hpfs_error(s, "bad EA in fnode %08lx",
 180                                                 (unsigned long)ino);
 181                                         goto bail;
 182                                 }
 183                                 ea = next_ea(ea);
 184                         }
 185                 }
 186         }
 187         return fnode;
 188         bail:
 189         brelse(*bhp);
 190         return NULL;
 191 }
 192
 193 struct anode *hpfs_map_anode(struct super_block *s, anode_secno ano, struct buffer_head **bhp)
 194 {
 195         struct anode *anode;
 196         if (hpfs_sb(s)->sb_chk) if (hpfs_chk_sectors(s, ano, 1, "anode")) return NULL;
 197         if ((anode = hpfs_map_sector(s, ano, bhp, ANODE_RD_AHEAD)))
 198                 if (hpfs_sb(s)->sb_chk) {
 199                         if (le32_to_cpu(anode->magic) != ANODE_MAGIC) {
 200                                 hpfs_error(s, "bad magic on anode %08x", ano);
 201                                 goto bail;
 202                         }
 203                         if (le32_to_cpu(anode->self) != ano) {
 204                                 hpfs_error(s, "self pointer invalid on anode %08x", ano);
 205                                 goto bail;
 206                         }
 207                         if ((unsigned)anode->btree.n_used_nodes + (unsigned)anode->btree.n_free_nodes !=
 208                             (bp_internal(&anode->btree) ? 60 : 40)) {
 209                                 hpfs_error(s, "bad number of nodes in anode %08x", ano);
 210                                 goto bail;
 211                         }
 212                         if (le16_to_cpu(anode->btree.first_free) !=
 213                             8 + anode->btree.n_used_nodes * (bp_internal(&anode->btree) ? 8 : 12)) {
 214                                 hpfs_error(s, "bad first_free pointer in anode %08x", ano);
 215                                 goto bail;
 216                         }
 217                 }
 218         return anode;
 219         bail:
 220         brelse(*bhp);
 221         return NULL;
 222 }
 223
 224 /*
 225  * Load dnode to memory and do some checks
 226  */
 227
 228 struct dnode *hpfs_map_dnode(struct super_block *s, unsigned secno,
 229                              struct quad_buffer_head *qbh)
 230 {
 231         struct dnode *dnode;
 232         if (hpfs_sb(s)->sb_chk) {
 233                 if (hpfs_chk_sectors(s, secno, 4, "dnode")) return NULL;
 234                 if (secno & 3) {
 235                         hpfs_error(s, "dnode %08x not byte-aligned", secno);
 236                         return NULL;
 237                 }
 238         }
 239         if ((dnode = hpfs_map_4sectors(s, secno, qbh, DNODE_RD_AHEAD)))
 240                 if (hpfs_sb(s)->sb_chk) {
 241                         unsigned p, pp = 0;
 242                         unsigned char *d = (unsigned char *)dnode;
 243                         int b = 0;
 244                         if (le32_to_cpu(dnode->magic) != DNODE_MAGIC) {
 245                                 hpfs_error(s, "bad magic on dnode %08x", secno);
 246                                 goto bail;
 247                         }
 248                         if (le32_to_cpu(dnode->self) != secno)
 249                                 hpfs_error(s, "bad self pointer on dnode %08x self = %08x", secno, le32_to_cpu(dnode->self));
 250                         /* Check dirents - bad dirents would cause infinite
 251                            loops or shooting to memory */
 252                         if (le32_to_cpu(dnode->first_free) > 2048) {
 253                                 hpfs_error(s, "dnode %08x has first_free == %08x", secno, le32_to_cpu(dnode->first_free));
 254                                 goto bail;
 255                         }
 256                         for (p = 20; p < le32_to_cpu(dnode->first_free); p += d[p] + (d[p+1] << 8)) {
 257                                 struct hpfs_dirent *de = (struct hpfs_dirent *)((char *)dnode + p);
 258                                 if (le16_to_cpu(de->length) > 292 || (le16_to_cpu(de->length) < 32) || (le16_to_cpu(de->length) & 3) || p + le16_to_cpu(de->length) > 2048) {
 259                                         hpfs_error(s, "bad dirent size in dnode %08x, dirent %03x, last %03x", secno, p, pp);
 260                                         goto bail;
 261                                 }
 262                                 if (((31 + de->namelen + de->down*4 + 3) & ~3) != le16_to_cpu(de->length)) {
 263                                         if (((31 + de->namelen + de->down*4 + 3) & ~3) < le16_to_cpu(de->length) && s->s_flags & MS_RDONLY) goto ok;
 264                                         hpfs_error(s, "namelen does not match dirent size in dnode %08x, dirent %03x, last %03x", secno, p, pp);
 265                                         goto bail;
 266                                 }
 267                                 ok:
 268                                 if (hpfs_sb(s)->sb_chk >= 2) b |= 1 << de->down;
 269                                 if (de->down) if (de_down_pointer(de) < 0x10) {
 270                                         hpfs_error(s, "bad down pointer in dnode %08x, dirent %03x, last %03x", secno, p, pp);
 271                                         goto bail;
 272                                 }
 273                                 pp = p;
 274
 275                         }
 276                         if (p != le32_to_cpu(dnode->first_free)) {
 277                                 hpfs_error(s, "size on last dirent does not match first_free; dnode %08x", secno);
 278                                 goto bail;
 279                         }
 280                         if (d[pp + 30] != 1 || d[pp + 31] != 255) {
 281                                 hpfs_error(s, "dnode %08x does not end with \\377 entry", secno);
 282                                 goto bail;
 283                         }
 284                         if (b == 3) printk("HPFS: warning: unbalanced dnode tree, dnode %08x; see hpfs.txt 4 more info\n", secno);
 285                 }
 286         return dnode;
 287         bail:
 288         hpfs_brelse4(qbh);
 289         return NULL;
 290 }
 291
 292 dnode_secno hpfs_fnode_dno(struct super_block *s, ino_t ino)
 293 {
 294         struct buffer_head *bh;
 295         struct fnode *fnode;
 296         dnode_secno dno;
 297
 298         fnode = hpfs_map_fnode(s, ino, &bh);
 299         if (!fnode)
 300                 return 0;
 301
 302         dno = le32_to_cpu(fnode->u.external[0].disk_secno);
 303         brelse(bh);
 304         return dno;
 305 }