linux/fs/hpfs/map.c
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   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
  36void 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
  56unsigned 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
 137struct 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
 194struct 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
 229struct 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
 295dnode_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}
 309