linux/fs/hpfs/map.c
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   1// SPDX-License-Identifier: GPL-2.0
   2/*
   3 *  linux/fs/hpfs/map.c
   4 *
   5 *  Mikulas Patocka (mikulas@artax.karlin.mff.cuni.cz), 1998-1999
   6 *
   7 *  mapping structures to memory with some minimal checks
   8 */
   9
  10#include "hpfs_fn.h"
  11
  12__le32 *hpfs_map_dnode_bitmap(struct super_block *s, struct quad_buffer_head *qbh)
  13{
  14        return hpfs_map_4sectors(s, hpfs_sb(s)->sb_dmap, qbh, 0);
  15}
  16
  17__le32 *hpfs_map_bitmap(struct super_block *s, unsigned bmp_block,
  18                         struct quad_buffer_head *qbh, char *id)
  19{
  20        secno sec;
  21        __le32 *ret;
  22        unsigned n_bands = (hpfs_sb(s)->sb_fs_size + 0x3fff) >> 14;
  23        if (hpfs_sb(s)->sb_chk) if (bmp_block >= n_bands) {
  24                hpfs_error(s, "hpfs_map_bitmap called with bad parameter: %08x at %s", bmp_block, id);
  25                return NULL;
  26        }
  27        sec = le32_to_cpu(hpfs_sb(s)->sb_bmp_dir[bmp_block]);
  28        if (!sec || sec > hpfs_sb(s)->sb_fs_size-4) {
  29                hpfs_error(s, "invalid bitmap block pointer %08x -> %08x at %s", bmp_block, sec, id);
  30                return NULL;
  31        }
  32        ret = hpfs_map_4sectors(s, sec, qbh, 4);
  33        if (ret) hpfs_prefetch_bitmap(s, bmp_block + 1);
  34        return ret;
  35}
  36
  37void hpfs_prefetch_bitmap(struct super_block *s, unsigned bmp_block)
  38{
  39        unsigned to_prefetch, next_prefetch;
  40        unsigned n_bands = (hpfs_sb(s)->sb_fs_size + 0x3fff) >> 14;
  41        if (unlikely(bmp_block >= n_bands))
  42                return;
  43        to_prefetch = le32_to_cpu(hpfs_sb(s)->sb_bmp_dir[bmp_block]);
  44        if (unlikely(bmp_block + 1 >= n_bands))
  45                next_prefetch = 0;
  46        else
  47                next_prefetch = le32_to_cpu(hpfs_sb(s)->sb_bmp_dir[bmp_block + 1]);
  48        hpfs_prefetch_sectors(s, to_prefetch, 4 + 4 * (to_prefetch + 4 == next_prefetch));
  49}
  50
  51/*
  52 * Load first code page into kernel memory, return pointer to 256-byte array,
  53 * first 128 bytes are uppercasing table for chars 128-255, next 128 bytes are
  54 * lowercasing table
  55 */
  56
  57unsigned char *hpfs_load_code_page(struct super_block *s, secno cps)
  58{
  59        struct buffer_head *bh;
  60        secno cpds;
  61        unsigned cpi;
  62        unsigned char *ptr;
  63        unsigned char *cp_table;
  64        int i;
  65        struct code_page_data *cpd;
  66        struct code_page_directory *cp = hpfs_map_sector(s, cps, &bh, 0);
  67        if (!cp) return NULL;
  68        if (le32_to_cpu(cp->magic) != CP_DIR_MAGIC) {
  69                pr_err("Code page directory magic doesn't match (magic = %08x)\n",
  70                        le32_to_cpu(cp->magic));
  71                brelse(bh);
  72                return NULL;
  73        }
  74        if (!le32_to_cpu(cp->n_code_pages)) {
  75                pr_err("n_code_pages == 0\n");
  76                brelse(bh);
  77                return NULL;
  78        }
  79        cpds = le32_to_cpu(cp->array[0].code_page_data);
  80        cpi = le16_to_cpu(cp->array[0].index);
  81        brelse(bh);
  82
  83        if (cpi >= 3) {
  84                pr_err("Code page index out of array\n");
  85                return NULL;
  86        }
  87        
  88        if (!(cpd = hpfs_map_sector(s, cpds, &bh, 0))) return NULL;
  89        if (le16_to_cpu(cpd->offs[cpi]) > 0x178) {
  90                pr_err("Code page index out of sector\n");
  91                brelse(bh);
  92                return NULL;
  93        }
  94        ptr = (unsigned char *)cpd + le16_to_cpu(cpd->offs[cpi]) + 6;
  95        if (!(cp_table = kmalloc(256, GFP_KERNEL))) {
  96                pr_err("out of memory for code page table\n");
  97                brelse(bh);
  98                return NULL;
  99        }
 100        memcpy(cp_table, ptr, 128);
 101        brelse(bh);
 102
 103        /* Try to build lowercasing table from uppercasing one */
 104
 105        for (i=128; i<256; i++) cp_table[i]=i;
 106        for (i=128; i<256; i++) if (cp_table[i-128]!=i && cp_table[i-128]>=128)
 107                cp_table[cp_table[i-128]] = i;
 108        
 109        return cp_table;
 110}
 111
 112__le32 *hpfs_load_bitmap_directory(struct super_block *s, secno bmp)
 113{
 114        struct buffer_head *bh;
 115        int n = (hpfs_sb(s)->sb_fs_size + 0x200000 - 1) >> 21;
 116        int i;
 117        __le32 *b;
 118        if (!(b = kmalloc(n * 512, GFP_KERNEL))) {
 119                pr_err("can't allocate memory for bitmap directory\n");
 120                return NULL;
 121        }       
 122        for (i=0;i<n;i++) {
 123                __le32 *d = hpfs_map_sector(s, bmp+i, &bh, n - i - 1);
 124                if (!d) {
 125                        kfree(b);
 126                        return NULL;
 127                }
 128                memcpy((char *)b + 512 * i, d, 512);
 129                brelse(bh);
 130        }
 131        return b;
 132}
 133
 134void hpfs_load_hotfix_map(struct super_block *s, struct hpfs_spare_block *spareblock)
 135{
 136        struct quad_buffer_head qbh;
 137        __le32 *directory;
 138        u32 n_hotfixes, n_used_hotfixes;
 139        unsigned i;
 140
 141        n_hotfixes = le32_to_cpu(spareblock->n_spares);
 142        n_used_hotfixes = le32_to_cpu(spareblock->n_spares_used);
 143
 144        if (n_hotfixes > 256 || n_used_hotfixes > n_hotfixes) {
 145                hpfs_error(s, "invalid number of hotfixes: %u, used: %u", n_hotfixes, n_used_hotfixes);
 146                return;
 147        }
 148        if (!(directory = hpfs_map_4sectors(s, le32_to_cpu(spareblock->hotfix_map), &qbh, 0))) {
 149                hpfs_error(s, "can't load hotfix map");
 150                return;
 151        }
 152        for (i = 0; i < n_used_hotfixes; i++) {
 153                hpfs_sb(s)->hotfix_from[i] = le32_to_cpu(directory[i]);
 154                hpfs_sb(s)->hotfix_to[i] = le32_to_cpu(directory[n_hotfixes + i]);
 155        }
 156        hpfs_sb(s)->n_hotfixes = n_used_hotfixes;
 157        hpfs_brelse4(&qbh);
 158}
 159
 160/*
 161 * Load fnode to memory
 162 */
 163
 164struct fnode *hpfs_map_fnode(struct super_block *s, ino_t ino, struct buffer_head **bhp)
 165{
 166        struct fnode *fnode;
 167        if (hpfs_sb(s)->sb_chk) if (hpfs_chk_sectors(s, ino, 1, "fnode")) {
 168                return NULL;
 169        }
 170        if ((fnode = hpfs_map_sector(s, ino, bhp, FNODE_RD_AHEAD))) {
 171                if (hpfs_sb(s)->sb_chk) {
 172                        struct extended_attribute *ea;
 173                        struct extended_attribute *ea_end;
 174                        if (le32_to_cpu(fnode->magic) != FNODE_MAGIC) {
 175                                hpfs_error(s, "bad magic on fnode %08lx",
 176                                        (unsigned long)ino);
 177                                goto bail;
 178                        }
 179                        if (!fnode_is_dir(fnode)) {
 180                                if ((unsigned)fnode->btree.n_used_nodes + (unsigned)fnode->btree.n_free_nodes !=
 181                                    (bp_internal(&fnode->btree) ? 12 : 8)) {
 182                                        hpfs_error(s,
 183                                           "bad number of nodes in fnode %08lx",
 184                                            (unsigned long)ino);
 185                                        goto bail;
 186                                }
 187                                if (le16_to_cpu(fnode->btree.first_free) !=
 188                                    8 + fnode->btree.n_used_nodes * (bp_internal(&fnode->btree) ? 8 : 12)) {
 189                                        hpfs_error(s,
 190                                            "bad first_free pointer in fnode %08lx",
 191                                            (unsigned long)ino);
 192                                        goto bail;
 193                                }
 194                        }
 195                        if (le16_to_cpu(fnode->ea_size_s) && (le16_to_cpu(fnode->ea_offs) < 0xc4 ||
 196                           le16_to_cpu(fnode->ea_offs) + le16_to_cpu(fnode->acl_size_s) + le16_to_cpu(fnode->ea_size_s) > 0x200)) {
 197                                hpfs_error(s,
 198                                        "bad EA info in fnode %08lx: ea_offs == %04x ea_size_s == %04x",
 199                                        (unsigned long)ino,
 200                                        le16_to_cpu(fnode->ea_offs), le16_to_cpu(fnode->ea_size_s));
 201                                goto bail;
 202                        }
 203                        ea = fnode_ea(fnode);
 204                        ea_end = fnode_end_ea(fnode);
 205                        while (ea != ea_end) {
 206                                if (ea > ea_end) {
 207                                        hpfs_error(s, "bad EA in fnode %08lx",
 208                                                (unsigned long)ino);
 209                                        goto bail;
 210                                }
 211                                ea = next_ea(ea);
 212                        }
 213                }
 214        }
 215        return fnode;
 216        bail:
 217        brelse(*bhp);
 218        return NULL;
 219}
 220
 221struct anode *hpfs_map_anode(struct super_block *s, anode_secno ano, struct buffer_head **bhp)
 222{
 223        struct anode *anode;
 224        if (hpfs_sb(s)->sb_chk) if (hpfs_chk_sectors(s, ano, 1, "anode")) return NULL;
 225        if ((anode = hpfs_map_sector(s, ano, bhp, ANODE_RD_AHEAD)))
 226                if (hpfs_sb(s)->sb_chk) {
 227                        if (le32_to_cpu(anode->magic) != ANODE_MAGIC) {
 228                                hpfs_error(s, "bad magic on anode %08x", ano);
 229                                goto bail;
 230                        }
 231                        if (le32_to_cpu(anode->self) != ano) {
 232                                hpfs_error(s, "self pointer invalid on anode %08x", ano);
 233                                goto bail;
 234                        }
 235                        if ((unsigned)anode->btree.n_used_nodes + (unsigned)anode->btree.n_free_nodes !=
 236                            (bp_internal(&anode->btree) ? 60 : 40)) {
 237                                hpfs_error(s, "bad number of nodes in anode %08x", ano);
 238                                goto bail;
 239                        }
 240                        if (le16_to_cpu(anode->btree.first_free) !=
 241                            8 + anode->btree.n_used_nodes * (bp_internal(&anode->btree) ? 8 : 12)) {
 242                                hpfs_error(s, "bad first_free pointer in anode %08x", ano);
 243                                goto bail;
 244                        }
 245                }
 246        return anode;
 247        bail:
 248        brelse(*bhp);
 249        return NULL;
 250}
 251
 252/*
 253 * Load dnode to memory and do some checks
 254 */
 255
 256struct dnode *hpfs_map_dnode(struct super_block *s, unsigned secno,
 257                             struct quad_buffer_head *qbh)
 258{
 259        struct dnode *dnode;
 260        if (hpfs_sb(s)->sb_chk) {
 261                if (hpfs_chk_sectors(s, secno, 4, "dnode")) return NULL;
 262                if (secno & 3) {
 263                        hpfs_error(s, "dnode %08x not byte-aligned", secno);
 264                        return NULL;
 265                }       
 266        }
 267        if ((dnode = hpfs_map_4sectors(s, secno, qbh, DNODE_RD_AHEAD)))
 268                if (hpfs_sb(s)->sb_chk) {
 269                        unsigned p, pp = 0;
 270                        unsigned char *d = (unsigned char *)dnode;
 271                        int b = 0;
 272                        if (le32_to_cpu(dnode->magic) != DNODE_MAGIC) {
 273                                hpfs_error(s, "bad magic on dnode %08x", secno);
 274                                goto bail;
 275                        }
 276                        if (le32_to_cpu(dnode->self) != secno)
 277                                hpfs_error(s, "bad self pointer on dnode %08x self = %08x", secno, le32_to_cpu(dnode->self));
 278                        /* Check dirents - bad dirents would cause infinite
 279                           loops or shooting to memory */
 280                        if (le32_to_cpu(dnode->first_free) > 2048) {
 281                                hpfs_error(s, "dnode %08x has first_free == %08x", secno, le32_to_cpu(dnode->first_free));
 282                                goto bail;
 283                        }
 284                        for (p = 20; p < le32_to_cpu(dnode->first_free); p += d[p] + (d[p+1] << 8)) {
 285                                struct hpfs_dirent *de = (struct hpfs_dirent *)((char *)dnode + p);
 286                                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) {
 287                                        hpfs_error(s, "bad dirent size in dnode %08x, dirent %03x, last %03x", secno, p, pp);
 288                                        goto bail;
 289                                }
 290                                if (((31 + de->namelen + de->down*4 + 3) & ~3) != le16_to_cpu(de->length)) {
 291                                        if (((31 + de->namelen + de->down*4 + 3) & ~3) < le16_to_cpu(de->length) && s->s_flags & MS_RDONLY) goto ok;
 292                                        hpfs_error(s, "namelen does not match dirent size in dnode %08x, dirent %03x, last %03x", secno, p, pp);
 293                                        goto bail;
 294                                }
 295                                ok:
 296                                if (hpfs_sb(s)->sb_chk >= 2) b |= 1 << de->down;
 297                                if (de->down) if (de_down_pointer(de) < 0x10) {
 298                                        hpfs_error(s, "bad down pointer in dnode %08x, dirent %03x, last %03x", secno, p, pp);
 299                                        goto bail;
 300                                }
 301                                pp = p;
 302                                
 303                        }
 304                        if (p != le32_to_cpu(dnode->first_free)) {
 305                                hpfs_error(s, "size on last dirent does not match first_free; dnode %08x", secno);
 306                                goto bail;
 307                        }
 308                        if (d[pp + 30] != 1 || d[pp + 31] != 255) {
 309                                hpfs_error(s, "dnode %08x does not end with \\377 entry", secno);
 310                                goto bail;
 311                        }
 312                        if (b == 3)
 313                                pr_err("unbalanced dnode tree, dnode %08x; see hpfs.txt 4 more info\n",
 314                                        secno);
 315                }
 316        return dnode;
 317        bail:
 318        hpfs_brelse4(qbh);
 319        return NULL;
 320}
 321
 322dnode_secno hpfs_fnode_dno(struct super_block *s, ino_t ino)
 323{
 324        struct buffer_head *bh;
 325        struct fnode *fnode;
 326        dnode_secno dno;
 327
 328        fnode = hpfs_map_fnode(s, ino, &bh);
 329        if (!fnode)
 330                return 0;
 331
 332        dno = le32_to_cpu(fnode->u.external[0].disk_secno);
 333        brelse(bh);
 334        return dno;
 335}
 336