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                 pr_err("Code page directory magic doesn't match (magic = %08x)\n",
  69                         le32_to_cpu(cp->magic));
  70                 brelse(bh);
  71                 return NULL;
  72         }
  73         if (!le32_to_cpu(cp->n_code_pages)) {
  74                 pr_err("n_code_pages == 0\n");
  75                 brelse(bh);
  76                 return NULL;
  77         }
  78         cpds = le32_to_cpu(cp->array[0].code_page_data);
  79         cpi = le16_to_cpu(cp->array[0].index);
  80         brelse(bh);
  81
  82         if (cpi >= 3) {
  83                 pr_err("Code page index out of array\n");
  84                 return NULL;
  85         }
  86
  87         if (!(cpd = hpfs_map_sector(s, cpds, &bh, 0))) return NULL;
  88         if (le16_to_cpu(cpd->offs[cpi]) > 0x178) {
  89                 pr_err("Code page index out of sector\n");
  90                 brelse(bh);
  91                 return NULL;
  92         }
  93         ptr = (unsigned char *)cpd + le16_to_cpu(cpd->offs[cpi]) + 6;
  94         if (!(cp_table = kmalloc(256, GFP_KERNEL))) {
  95                 pr_err("out of memory for code page table\n");
  96                 brelse(bh);
  97                 return NULL;
  98         }
  99         memcpy(cp_table, ptr, 128);
 100         brelse(bh);
 101
 102         /* Try to build lowercasing table from uppercasing one */
 103
 104         for (i=128; i<256; i++) cp_table[i]=i;
 105         for (i=128; i<256; i++) if (cp_table[i-128]!=i && cp_table[i-128]>=128)
 106                 cp_table[cp_table[i-128]] = i;
 107
 108         return cp_table;
 109 }
 110
 111 __le32 *hpfs_load_bitmap_directory(struct super_block *s, secno bmp)
 112 {
 113         struct buffer_head *bh;
 114         int n = (hpfs_sb(s)->sb_fs_size + 0x200000 - 1) >> 21;
 115         int i;
 116         __le32 *b;
 117         if (!(b = kmalloc(n * 512, GFP_KERNEL))) {
 118                 pr_err("can't allocate memory for bitmap directory\n");
 119                 return NULL;
 120         }
 121         for (i=0;i<n;i++) {
 122                 __le32 *d = hpfs_map_sector(s, bmp+i, &bh, n - i - 1);
 123                 if (!d) {
 124                         kfree(b);
 125                         return NULL;
 126                 }
 127                 memcpy((char *)b + 512 * i, d, 512);
 128                 brelse(bh);
 129         }
 130         return b;
 131 }
 132
 133 /*
 134  * Load fnode to memory
 135  */
 136
 137 struct fnode *hpfs_map_fnode(struct super_block *s, ino_t ino, struct buffer_head **bhp)
 138 {
 139         struct fnode *fnode;
 140         if (hpfs_sb(s)->sb_chk) if (hpfs_chk_sectors(s, ino, 1, "fnode")) {
 141                 return NULL;
 142         }
 143         if ((fnode = hpfs_map_sector(s, ino, bhp, FNODE_RD_AHEAD))) {
 144                 if (hpfs_sb(s)->sb_chk) {
 145                         struct extended_attribute *ea;
 146                         struct extended_attribute *ea_end;
 147                         if (le32_to_cpu(fnode->magic) != FNODE_MAGIC) {
 148                                 hpfs_error(s, "bad magic on fnode %08lx",
 149                                         (unsigned long)ino);
 150                                 goto bail;
 151                         }
 152                         if (!fnode_is_dir(fnode)) {
 153                                 if ((unsigned)fnode->btree.n_used_nodes + (unsigned)fnode->btree.n_free_nodes !=
 154                                     (bp_internal(&fnode->btree) ? 12 : 8)) {
 155                                         hpfs_error(s,
 156                                            "bad number of nodes in fnode %08lx",
 157                                             (unsigned long)ino);
 158                                         goto bail;
 159                                 }
 160                                 if (le16_to_cpu(fnode->btree.first_free) !=
 161                                     8 + fnode->btree.n_used_nodes * (bp_internal(&fnode->btree) ? 8 : 12)) {
 162                                         hpfs_error(s,
 163                                             "bad first_free pointer in fnode %08lx",
 164                                             (unsigned long)ino);
 165                                         goto bail;
 166                                 }
 167                         }
 168                         if (le16_to_cpu(fnode->ea_size_s) && (le16_to_cpu(fnode->ea_offs) < 0xc4 ||
 169                            le16_to_cpu(fnode->ea_offs) + le16_to_cpu(fnode->acl_size_s) + le16_to_cpu(fnode->ea_size_s) > 0x200)) {
 170                                 hpfs_error(s,
 171                                         "bad EA info in fnode %08lx: ea_offs == %04x ea_size_s == %04x",
 172                                         (unsigned long)ino,
 173                                         le16_to_cpu(fnode->ea_offs), le16_to_cpu(fnode->ea_size_s));
 174                                 goto bail;
 175                         }
 176                         ea = fnode_ea(fnode);
 177                         ea_end = fnode_end_ea(fnode);
 178                         while (ea != ea_end) {
 179                                 if (ea > ea_end) {
 180                                         hpfs_error(s, "bad EA in fnode %08lx",
 181                                                 (unsigned long)ino);
 182                                         goto bail;
 183                                 }
 184                                 ea = next_ea(ea);
 185                         }
 186                 }
 187         }
 188         return fnode;
 189         bail:
 190         brelse(*bhp);
 191         return NULL;
 192 }
 193
 194 struct anode *hpfs_map_anode(struct super_block *s, anode_secno ano, struct buffer_head **bhp)
 195 {
 196         struct anode *anode;
 197         if (hpfs_sb(s)->sb_chk) if (hpfs_chk_sectors(s, ano, 1, "anode")) return NULL;
 198         if ((anode = hpfs_map_sector(s, ano, bhp, ANODE_RD_AHEAD)))
 199                 if (hpfs_sb(s)->sb_chk) {
 200                         if (le32_to_cpu(anode->magic) != ANODE_MAGIC) {
 201                                 hpfs_error(s, "bad magic on anode %08x", ano);
 202                                 goto bail;
 203                         }
 204                         if (le32_to_cpu(anode->self) != ano) {
 205                                 hpfs_error(s, "self pointer invalid on anode %08x", ano);
 206                                 goto bail;
 207                         }
 208                         if ((unsigned)anode->btree.n_used_nodes + (unsigned)anode->btree.n_free_nodes !=
 209                             (bp_internal(&anode->btree) ? 60 : 40)) {
 210                                 hpfs_error(s, "bad number of nodes in anode %08x", ano);
 211                                 goto bail;
 212                         }
 213                         if (le16_to_cpu(anode->btree.first_free) !=
 214                             8 + anode->btree.n_used_nodes * (bp_internal(&anode->btree) ? 8 : 12)) {
 215                                 hpfs_error(s, "bad first_free pointer in anode %08x", ano);
 216                                 goto bail;
 217                         }
 218                 }
 219         return anode;
 220         bail:
 221         brelse(*bhp);
 222         return NULL;
 223 }
 224
 225 /*
 226  * Load dnode to memory and do some checks
 227  */
 228
 229 struct dnode *hpfs_map_dnode(struct super_block *s, unsigned secno,
 230                              struct quad_buffer_head *qbh)
 231 {
 232         struct dnode *dnode;
 233         if (hpfs_sb(s)->sb_chk) {
 234                 if (hpfs_chk_sectors(s, secno, 4, "dnode")) return NULL;
 235                 if (secno & 3) {
 236                         hpfs_error(s, "dnode %08x not byte-aligned", secno);
 237                         return NULL;
 238                 }
 239         }
 240         if ((dnode = hpfs_map_4sectors(s, secno, qbh, DNODE_RD_AHEAD)))
 241                 if (hpfs_sb(s)->sb_chk) {
 242                         unsigned p, pp = 0;
 243                         unsigned char *d = (unsigned char *)dnode;
 244                         int b = 0;
 245                         if (le32_to_cpu(dnode->magic) != DNODE_MAGIC) {
 246                                 hpfs_error(s, "bad magic on dnode %08x", secno);
 247                                 goto bail;
 248                         }
 249                         if (le32_to_cpu(dnode->self) != secno)
 250                                 hpfs_error(s, "bad self pointer on dnode %08x self = %08x", secno, le32_to_cpu(dnode->self));
 251                         /* Check dirents - bad dirents would cause infinite
 252                            loops or shooting to memory */
 253                         if (le32_to_cpu(dnode->first_free) > 2048) {
 254                                 hpfs_error(s, "dnode %08x has first_free == %08x", secno, le32_to_cpu(dnode->first_free));
 255                                 goto bail;
 256                         }
 257                         for (p = 20; p < le32_to_cpu(dnode->first_free); p += d[p] + (d[p+1] << 8)) {
 258                                 struct hpfs_dirent *de = (struct hpfs_dirent *)((char *)dnode + p);
 259                                 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) {
 260                                         hpfs_error(s, "bad dirent size in dnode %08x, dirent %03x, last %03x", secno, p, pp);
 261                                         goto bail;
 262                                 }
 263                                 if (((31 + de->namelen + de->down*4 + 3) & ~3) != le16_to_cpu(de->length)) {
 264                                         if (((31 + de->namelen + de->down*4 + 3) & ~3) < le16_to_cpu(de->length) && s->s_flags & MS_RDONLY) goto ok;
 265                                         hpfs_error(s, "namelen does not match dirent size in dnode %08x, dirent %03x, last %03x", secno, p, pp);
 266                                         goto bail;
 267                                 }
 268                                 ok:
 269                                 if (hpfs_sb(s)->sb_chk >= 2) b |= 1 << de->down;
 270                                 if (de->down) if (de_down_pointer(de) < 0x10) {
 271                                         hpfs_error(s, "bad down pointer in dnode %08x, dirent %03x, last %03x", secno, p, pp);
 272                                         goto bail;
 273                                 }
 274                                 pp = p;
 275
 276                         }
 277                         if (p != le32_to_cpu(dnode->first_free)) {
 278                                 hpfs_error(s, "size on last dirent does not match first_free; dnode %08x", secno);
 279                                 goto bail;
 280                         }
 281                         if (d[pp + 30] != 1 || d[pp + 31] != 255) {
 282                                 hpfs_error(s, "dnode %08x does not end with \\377 entry", secno);
 283                                 goto bail;
 284                         }
 285                         if (b == 3)
 286                                 pr_err("unbalanced dnode tree, dnode %08x; see hpfs.txt 4 more info\n",
 287                                         secno);
 288                 }
 289         return dnode;
 290         bail:
 291         hpfs_brelse4(qbh);
 292         return NULL;
 293 }
 294
 295 dnode_secno hpfs_fnode_dno(struct super_block *s, ino_t ino)
 296 {
 297         struct buffer_head *bh;
 298         struct fnode *fnode;
 299         dnode_secno dno;
 300
 301         fnode = hpfs_map_fnode(s, ino, &bh);
 302         if (!fnode)
 303                 return 0;
 304
 305         dno = le32_to_cpu(fnode->u.external[0].disk_secno);
 306         brelse(bh);
 307         return dno;
 308 }