git.oblomov.eu Git - linux-2.6/blob - 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, hpfs_sb(s)->sb_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 (hpfs_sb(s)->sb_chk) if (bmp_block * 16384 > hpfs_sb(s)->sb_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 = hpfs_sb(s)->sb_bmp_dir[bmp_block];
  25         if (!sec || sec > hpfs_sb(s)->sb_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 = (hpfs_sb(s)->sb_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 (hpfs_sb(s)->sb_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 (hpfs_sb(s)->sb_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 %08lx",
 130                                         (unsigned long)ino);
 131                                 goto bail;
 132                         }
 133                         if (!fnode->dirflag) {
 134                                 if ((unsigned)fnode->btree.n_used_nodes + (unsigned)fnode->btree.n_free_nodes !=
 135                                     (fnode->btree.internal ? 12 : 8)) {
 136                                         hpfs_error(s,
 137                                            "bad number of nodes in fnode %08lx",
 138                                             (unsigned long)ino);
 139                                         goto bail;
 140                                 }
 141                                 if (fnode->btree.first_free !=
 142                                     8 + fnode->btree.n_used_nodes * (fnode->btree.internal ? 8 : 12)) {
 143                                         hpfs_error(s,
 144                                             "bad first_free pointer in fnode %08lx",
 145                                             (unsigned long)ino);
 146                                         goto bail;
 147                                 }
 148                         }
 149                         if (fnode->ea_size_s && ((signed int)fnode->ea_offs < 0xc4 ||
 150                            (signed int)fnode->ea_offs + fnode->acl_size_s + fnode->ea_size_s > 0x200)) {
 151                                 hpfs_error(s,
 152                                         "bad EA info in fnode %08lx: ea_offs == %04x ea_size_s == %04x",
 153                                         (unsigned long)ino,
 154                                         fnode->ea_offs, fnode->ea_size_s);
 155                                 goto bail;
 156                         }
 157                         ea = fnode_ea(fnode);
 158                         ea_end = fnode_end_ea(fnode);
 159                         while (ea != ea_end) {
 160                                 if (ea > ea_end) {
 161                                         hpfs_error(s, "bad EA in fnode %08lx",
 162                                                 (unsigned long)ino);
 163                                         goto bail;
 164                                 }
 165                                 ea = next_ea(ea);
 166                         }
 167                 }
 168         }
 169         return fnode;
 170         bail:
 171         brelse(*bhp);
 172         return NULL;
 173 }
 174
 175 struct anode *hpfs_map_anode(struct super_block *s, anode_secno ano, struct buffer_head **bhp)
 176 {
 177         struct anode *anode;
 178         if (hpfs_sb(s)->sb_chk) if (hpfs_chk_sectors(s, ano, 1, "anode")) return NULL;
 179         if ((anode = hpfs_map_sector(s, ano, bhp, ANODE_RD_AHEAD)))
 180                 if (hpfs_sb(s)->sb_chk) {
 181                         if (anode->magic != ANODE_MAGIC || anode->self != ano) {
 182                                 hpfs_error(s, "bad magic on anode %08x", ano);
 183                                 goto bail;
 184                         }
 185                         if ((unsigned)anode->btree.n_used_nodes + (unsigned)anode->btree.n_free_nodes !=
 186                             (anode->btree.internal ? 60 : 40)) {
 187                                 hpfs_error(s, "bad number of nodes in anode %08x", ano);
 188                                 goto bail;
 189                         }
 190                         if (anode->btree.first_free !=
 191                             8 + anode->btree.n_used_nodes * (anode->btree.internal ? 8 : 12)) {
 192                                 hpfs_error(s, "bad first_free pointer in anode %08x", ano);
 193                                 goto bail;
 194                         }
 195                 }
 196         return anode;
 197         bail:
 198         brelse(*bhp);
 199         return NULL;
 200 }
 201
 202 /*
 203  * Load dnode to memory and do some checks
 204  */
 205
 206 struct dnode *hpfs_map_dnode(struct super_block *s, unsigned secno,
 207                              struct quad_buffer_head *qbh)
 208 {
 209         struct dnode *dnode;
 210         if (hpfs_sb(s)->sb_chk) {
 211                 if (hpfs_chk_sectors(s, secno, 4, "dnode")) return NULL;
 212                 if (secno & 3) {
 213                         hpfs_error(s, "dnode %08x not byte-aligned", secno);
 214                         return NULL;
 215                 }
 216         }
 217         if ((dnode = hpfs_map_4sectors(s, secno, qbh, DNODE_RD_AHEAD)))
 218                 if (hpfs_sb(s)->sb_chk) {
 219                         unsigned p, pp = 0;
 220                         unsigned char *d = (char *)dnode;
 221                         int b = 0;
 222                         if (dnode->magic != DNODE_MAGIC) {
 223                                 hpfs_error(s, "bad magic on dnode %08x", secno);
 224                                 goto bail;
 225                         }
 226                         if (dnode->self != secno)
 227                                 hpfs_error(s, "bad self pointer on dnode %08x self = %08x", secno, dnode->self);
 228                         /* Check dirents - bad dirents would cause infinite
 229                            loops or shooting to memory */
 230                         if (dnode->first_free > 2048/* || dnode->first_free < 84*/) {
 231                                 hpfs_error(s, "dnode %08x has first_free == %08x", secno, dnode->first_free);
 232                                 goto bail;
 233                         }
 234                         for (p = 20; p < dnode->first_free; p += d[p] + (d[p+1] << 8)) {
 235                                 struct hpfs_dirent *de = (struct hpfs_dirent *)((char *)dnode + p);
 236                                 if (de->length > 292 || (de->length < 32) || (de->length & 3) || p + de->length > 2048) {
 237                                         hpfs_error(s, "bad dirent size in dnode %08x, dirent %03x, last %03x", secno, p, pp);
 238                                         goto bail;
 239                                 }
 240                                 if (((31 + de->namelen + de->down*4 + 3) & ~3) != de->length) {
 241                                         if (((31 + de->namelen + de->down*4 + 3) & ~3) < de->length && s->s_flags & MS_RDONLY) goto ok;
 242                                         hpfs_error(s, "namelen does not match dirent size in dnode %08x, dirent %03x, last %03x", secno, p, pp);
 243                                         goto bail;
 244                                 }
 245                                 ok:
 246                                 if (hpfs_sb(s)->sb_chk >= 2) b |= 1 << de->down;
 247                                 if (de->down) if (de_down_pointer(de) < 0x10) {
 248                                         hpfs_error(s, "bad down pointer in dnode %08x, dirent %03x, last %03x", secno, p, pp);
 249                                         goto bail;
 250                                 }
 251                                 pp = p;
 252
 253                         }
 254                         if (p != dnode->first_free) {
 255                                 hpfs_error(s, "size on last dirent does not match first_free; dnode %08x", secno);
 256                                 goto bail;
 257                         }
 258                         if (d[pp + 30] != 1 || d[pp + 31] != 255) {
 259                                 hpfs_error(s, "dnode %08x does not end with \\377 entry", secno);
 260                                 goto bail;
 261                         }
 262                         if (b == 3) printk("HPFS: warning: unbalanced dnode tree, dnode %08x; see hpfs.txt 4 more info\n", secno);
 263                 }
 264         return dnode;
 265         bail:
 266         hpfs_brelse4(qbh);
 267         return NULL;
 268 }
 269
 270 dnode_secno hpfs_fnode_dno(struct super_block *s, ino_t ino)
 271 {
 272         struct buffer_head *bh;
 273         struct fnode *fnode;
 274         dnode_secno dno;
 275
 276         fnode = hpfs_map_fnode(s, ino, &bh);
 277         if (!fnode)
 278                 return 0;
 279
 280         dno = fnode->u.external[0].disk_secno;
 281         brelse(bh);
 282         return dno;
 283 }