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 void hpfs_load_hotfix_map(struct super_block *s, struct hpfs_spare_block *spareblock)
 134 {
 135         struct quad_buffer_head qbh;
 136         __le32 *directory;
 137         u32 n_hotfixes, n_used_hotfixes;
 138         unsigned i;
 139
 140         n_hotfixes = le32_to_cpu(spareblock->n_spares);
 141         n_used_hotfixes = le32_to_cpu(spareblock->n_spares_used);
 142
 143         if (n_hotfixes > 256 || n_used_hotfixes > n_hotfixes) {
 144                 hpfs_error(s, "invalid number of hotfixes: %u, used: %u", n_hotfixes, n_used_hotfixes);
 145                 return;
 146         }
 147         if (!(directory = hpfs_map_4sectors(s, le32_to_cpu(spareblock->hotfix_map), &qbh, 0))) {
 148                 hpfs_error(s, "can't load hotfix map");
 149                 return;
 150         }
 151         for (i = 0; i < n_used_hotfixes; i++) {
 152                 hpfs_sb(s)->hotfix_from[i] = le32_to_cpu(directory[i]);
 153                 hpfs_sb(s)->hotfix_to[i] = le32_to_cpu(directory[n_hotfixes + i]);
 154         }
 155         hpfs_sb(s)->n_hotfixes = n_used_hotfixes;
 156         hpfs_brelse4(&qbh);
 157 }
 158
 159 /*
 160  * Load fnode to memory
 161  */
 162
 163 struct fnode *hpfs_map_fnode(struct super_block *s, ino_t ino, struct buffer_head **bhp)
 164 {
 165         struct fnode *fnode;
 166         if (hpfs_sb(s)->sb_chk) if (hpfs_chk_sectors(s, ino, 1, "fnode")) {
 167                 return NULL;
 168         }
 169         if ((fnode = hpfs_map_sector(s, ino, bhp, FNODE_RD_AHEAD))) {
 170                 if (hpfs_sb(s)->sb_chk) {
 171                         struct extended_attribute *ea;
 172                         struct extended_attribute *ea_end;
 173                         if (le32_to_cpu(fnode->magic) != FNODE_MAGIC) {
 174                                 hpfs_error(s, "bad magic on fnode %08lx",
 175                                         (unsigned long)ino);
 176                                 goto bail;
 177                         }
 178                         if (!fnode_is_dir(fnode)) {
 179                                 if ((unsigned)fnode->btree.n_used_nodes + (unsigned)fnode->btree.n_free_nodes !=
 180                                     (bp_internal(&fnode->btree) ? 12 : 8)) {
 181                                         hpfs_error(s,
 182                                            "bad number of nodes in fnode %08lx",
 183                                             (unsigned long)ino);
 184                                         goto bail;
 185                                 }
 186                                 if (le16_to_cpu(fnode->btree.first_free) !=
 187                                     8 + fnode->btree.n_used_nodes * (bp_internal(&fnode->btree) ? 8 : 12)) {
 188                                         hpfs_error(s,
 189                                             "bad first_free pointer in fnode %08lx",
 190                                             (unsigned long)ino);
 191                                         goto bail;
 192                                 }
 193                         }
 194                         if (le16_to_cpu(fnode->ea_size_s) && (le16_to_cpu(fnode->ea_offs) < 0xc4 ||
 195                            le16_to_cpu(fnode->ea_offs) + le16_to_cpu(fnode->acl_size_s) + le16_to_cpu(fnode->ea_size_s) > 0x200)) {
 196                                 hpfs_error(s,
 197                                         "bad EA info in fnode %08lx: ea_offs == %04x ea_size_s == %04x",
 198                                         (unsigned long)ino,
 199                                         le16_to_cpu(fnode->ea_offs), le16_to_cpu(fnode->ea_size_s));
 200                                 goto bail;
 201                         }
 202                         ea = fnode_ea(fnode);
 203                         ea_end = fnode_end_ea(fnode);
 204                         while (ea != ea_end) {
 205                                 if (ea > ea_end) {
 206                                         hpfs_error(s, "bad EA in fnode %08lx",
 207                                                 (unsigned long)ino);
 208                                         goto bail;
 209                                 }
 210                                 ea = next_ea(ea);
 211                         }
 212                 }
 213         }
 214         return fnode;
 215         bail:
 216         brelse(*bhp);
 217         return NULL;
 218 }
 219
 220 struct anode *hpfs_map_anode(struct super_block *s, anode_secno ano, struct buffer_head **bhp)
 221 {
 222         struct anode *anode;
 223         if (hpfs_sb(s)->sb_chk) if (hpfs_chk_sectors(s, ano, 1, "anode")) return NULL;
 224         if ((anode = hpfs_map_sector(s, ano, bhp, ANODE_RD_AHEAD)))
 225                 if (hpfs_sb(s)->sb_chk) {
 226                         if (le32_to_cpu(anode->magic) != ANODE_MAGIC) {
 227                                 hpfs_error(s, "bad magic on anode %08x", ano);
 228                                 goto bail;
 229                         }
 230                         if (le32_to_cpu(anode->self) != ano) {
 231                                 hpfs_error(s, "self pointer invalid on anode %08x", ano);
 232                                 goto bail;
 233                         }
 234                         if ((unsigned)anode->btree.n_used_nodes + (unsigned)anode->btree.n_free_nodes !=
 235                             (bp_internal(&anode->btree) ? 60 : 40)) {
 236                                 hpfs_error(s, "bad number of nodes in anode %08x", ano);
 237                                 goto bail;
 238                         }
 239                         if (le16_to_cpu(anode->btree.first_free) !=
 240                             8 + anode->btree.n_used_nodes * (bp_internal(&anode->btree) ? 8 : 12)) {
 241                                 hpfs_error(s, "bad first_free pointer in anode %08x", ano);
 242                                 goto bail;
 243                         }
 244                 }
 245         return anode;
 246         bail:
 247         brelse(*bhp);
 248         return NULL;
 249 }
 250
 251 /*
 252  * Load dnode to memory and do some checks
 253  */
 254
 255 struct dnode *hpfs_map_dnode(struct super_block *s, unsigned secno,
 256                              struct quad_buffer_head *qbh)
 257 {
 258         struct dnode *dnode;
 259         if (hpfs_sb(s)->sb_chk) {
 260                 if (hpfs_chk_sectors(s, secno, 4, "dnode")) return NULL;
 261                 if (secno & 3) {
 262                         hpfs_error(s, "dnode %08x not byte-aligned", secno);
 263                         return NULL;
 264                 }
 265         }
 266         if ((dnode = hpfs_map_4sectors(s, secno, qbh, DNODE_RD_AHEAD)))
 267                 if (hpfs_sb(s)->sb_chk) {
 268                         unsigned p, pp = 0;
 269                         unsigned char *d = (unsigned char *)dnode;
 270                         int b = 0;
 271                         if (le32_to_cpu(dnode->magic) != DNODE_MAGIC) {
 272                                 hpfs_error(s, "bad magic on dnode %08x", secno);
 273                                 goto bail;
 274                         }
 275                         if (le32_to_cpu(dnode->self) != secno)
 276                                 hpfs_error(s, "bad self pointer on dnode %08x self = %08x", secno, le32_to_cpu(dnode->self));
 277                         /* Check dirents - bad dirents would cause infinite
 278                            loops or shooting to memory */
 279                         if (le32_to_cpu(dnode->first_free) > 2048) {
 280                                 hpfs_error(s, "dnode %08x has first_free == %08x", secno, le32_to_cpu(dnode->first_free));
 281                                 goto bail;
 282                         }
 283                         for (p = 20; p < le32_to_cpu(dnode->first_free); p += d[p] + (d[p+1] << 8)) {
 284                                 struct hpfs_dirent *de = (struct hpfs_dirent *)((char *)dnode + p);
 285                                 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) {
 286                                         hpfs_error(s, "bad dirent size in dnode %08x, dirent %03x, last %03x", secno, p, pp);
 287                                         goto bail;
 288                                 }
 289                                 if (((31 + de->namelen + de->down*4 + 3) & ~3) != le16_to_cpu(de->length)) {
 290                                         if (((31 + de->namelen + de->down*4 + 3) & ~3) < le16_to_cpu(de->length) && s->s_flags & MS_RDONLY) goto ok;
 291                                         hpfs_error(s, "namelen does not match dirent size in dnode %08x, dirent %03x, last %03x", secno, p, pp);
 292                                         goto bail;
 293                                 }
 294                                 ok:
 295                                 if (hpfs_sb(s)->sb_chk >= 2) b |= 1 << de->down;
 296                                 if (de->down) if (de_down_pointer(de) < 0x10) {
 297                                         hpfs_error(s, "bad down pointer in dnode %08x, dirent %03x, last %03x", secno, p, pp);
 298                                         goto bail;
 299                                 }
 300                                 pp = p;
 301
 302                         }
 303                         if (p != le32_to_cpu(dnode->first_free)) {
 304                                 hpfs_error(s, "size on last dirent does not match first_free; dnode %08x", secno);
 305                                 goto bail;
 306                         }
 307                         if (d[pp + 30] != 1 || d[pp + 31] != 255) {
 308                                 hpfs_error(s, "dnode %08x does not end with \\377 entry", secno);
 309                                 goto bail;
 310                         }
 311                         if (b == 3)
 312                                 pr_err("unbalanced dnode tree, dnode %08x; see hpfs.txt 4 more info\n",
 313                                         secno);
 314                 }
 315         return dnode;
 316         bail:
 317         hpfs_brelse4(qbh);
 318         return NULL;
 319 }
 320
 321 dnode_secno hpfs_fnode_dno(struct super_block *s, ino_t ino)
 322 {
 323         struct buffer_head *bh;
 324         struct fnode *fnode;
 325         dnode_secno dno;
 326
 327         fnode = hpfs_map_fnode(s, ino, &bh);
 328         if (!fnode)
 329                 return 0;
 330
 331         dno = le32_to_cpu(fnode->u.external[0].disk_secno);
 332         brelse(bh);
 333         return dno;
 334 }