linux-old/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
  11unsigned *hpfs_map_dnode_bitmap(struct super_block *s, struct quad_buffer_head *qbh)
  12{
  13        return hpfs_map_4sectors(s, s->s_hpfs_dmap, qbh, 0);
  14}
  15
  16unsigned 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 (s->s_hpfs_chk) if (bmp_block * 16384 > s->s_hpfs_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 = s->s_hpfs_bmp_dir[bmp_block];
  25        if (!sec || sec > s->s_hpfs_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
  38char *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
  92secno *hpfs_load_bitmap_directory(struct super_block *s, secno bmp)
  93{
  94        struct buffer_head *bh;
  95        int n = (s->s_hpfs_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
 118struct fnode *hpfs_map_fnode(struct super_block *s, ino_t ino, struct buffer_head **bhp)
 119{
 120        struct fnode *fnode;
 121        if (s->s_hpfs_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 (s->s_hpfs_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 %08x", ino);
 130                                goto bail;
 131                        }
 132                        if (!fnode->dirflag) {
 133                                if ((unsigned)fnode->btree.n_used_nodes + (unsigned)fnode->btree.n_free_nodes !=
 134                                    (fnode->btree.internal ? 12 : 8)) {
 135                                        hpfs_error(s, "bad number of nodes in fnode %08x", ino);
 136                                        goto bail;
 137                                }
 138                                if (fnode->btree.first_free !=
 139                                    8 + fnode->btree.n_used_nodes * (fnode->btree.internal ? 8 : 12)) {
 140                                        hpfs_error(s, "bad first_free pointer in fnode %08x", ino);
 141                                        goto bail;
 142                                }
 143                        }
 144                        if (fnode->ea_size_s && ((signed int)fnode->ea_offs < 0xc4 ||
 145                           (signed int)fnode->ea_offs + fnode->acl_size_s + fnode->ea_size_s > 0x200)) {
 146                                hpfs_error(s, "bad EA info in fnode %08x: ea_offs == %04x ea_size_s == %04x",
 147                                        ino, fnode->ea_offs, fnode->ea_size_s);
 148                                goto bail;
 149                        }
 150                        ea = fnode_ea(fnode);
 151                        ea_end = fnode_end_ea(fnode);
 152                        while (ea != ea_end) {
 153                                if (ea > ea_end) {
 154                                        hpfs_error(s, "bad EA in fnode %08x", ino);
 155                                        goto bail;
 156                                }
 157                                ea = next_ea(ea);
 158                        }
 159                }
 160        }
 161        return fnode;
 162        bail:
 163        brelse(*bhp);
 164        return NULL;
 165}
 166
 167struct anode *hpfs_map_anode(struct super_block *s, anode_secno ano, struct buffer_head **bhp)
 168{
 169        struct anode *anode;
 170        if (s->s_hpfs_chk) if (hpfs_chk_sectors(s, ano, 1, "anode")) return NULL;
 171        if ((anode = hpfs_map_sector(s, ano, bhp, ANODE_RD_AHEAD)))
 172                if (s->s_hpfs_chk) {
 173                        if (anode->magic != ANODE_MAGIC || anode->self != ano) {
 174                                hpfs_error(s, "bad magic on anode %08x", ano);
 175                                goto bail;
 176                        }
 177                        if ((unsigned)anode->btree.n_used_nodes + (unsigned)anode->btree.n_free_nodes !=
 178                            (anode->btree.internal ? 60 : 40)) {
 179                                hpfs_error(s, "bad number of nodes in anode %08x", ano);
 180                                goto bail;
 181                        }
 182                        if (anode->btree.first_free !=
 183                            8 + anode->btree.n_used_nodes * (anode->btree.internal ? 8 : 12)) {
 184                                hpfs_error(s, "bad first_free pointer in anode %08x", ano);
 185                                goto bail;
 186                        }
 187                }
 188        return anode;
 189        bail:
 190        brelse(*bhp);
 191        return NULL;
 192}
 193
 194/*
 195 * Load dnode to memory and do some checks
 196 */
 197
 198struct dnode *hpfs_map_dnode(struct super_block *s, unsigned secno,
 199                             struct quad_buffer_head *qbh)
 200{
 201        struct dnode *dnode;
 202        if (s->s_hpfs_chk) {
 203                if (hpfs_chk_sectors(s, secno, 4, "dnode")) return NULL;
 204                if (secno & 3) {
 205                        hpfs_error(s, "dnode %08x not byte-aligned", secno);
 206                        return NULL;
 207                }       
 208        }
 209        if ((dnode = hpfs_map_4sectors(s, secno, qbh, DNODE_RD_AHEAD)))
 210                if (s->s_hpfs_chk) {
 211                        unsigned p, pp = 0;
 212                        unsigned char *d = (char *)dnode;
 213                        int b = 0;
 214                        if (dnode->magic != DNODE_MAGIC) {
 215                                hpfs_error(s, "bad magic on dnode %08x", secno);
 216                                goto bail;
 217                        }
 218                        if (dnode->self != secno)
 219                                hpfs_error(s, "bad self pointer on dnode %08x self = %08x", secno, dnode->self);
 220                        /* Check dirents - bad dirents would cause infinite
 221                           loops or shooting to memory */
 222                        if (dnode->first_free > 2048/* || dnode->first_free < 84*/) {
 223                                hpfs_error(s, "dnode %08x has first_free == %08x", secno, dnode->first_free);
 224                                goto bail;
 225                        }
 226                        for (p = 20; p < dnode->first_free; p += d[p] + (d[p+1] << 8)) {
 227                                struct hpfs_dirent *de = (struct hpfs_dirent *)((char *)dnode + p);
 228                                if (de->length > 292 || (de->length < 32) || (de->length & 3) || p + de->length > 2048) {
 229                                        hpfs_error(s, "bad dirent size in dnode %08x, dirent %03x, last %03x", secno, p, pp);
 230                                        goto bail;
 231                                }
 232                                if (((31 + de->namelen + de->down*4 + 3) & ~3) != de->length) {
 233                                        if (((31 + de->namelen + de->down*4 + 3) & ~3) < de->length && s->s_flags & MS_RDONLY) goto ok;
 234                                        hpfs_error(s, "namelen does not match dirent size in dnode %08x, dirent %03x, last %03x", secno, p, pp);
 235                                        goto bail;
 236                                }
 237                                ok:
 238                                if (s->s_hpfs_chk >= 2) b |= 1 << de->down;
 239                                if (de->down) if (de_down_pointer(de) < 0x10) {
 240                                        hpfs_error(s, "bad down pointer in dnode %08x, dirent %03x, last %03x", secno, p, pp);
 241                                        goto bail;
 242                                }
 243                                pp = p;
 244                                
 245                        }
 246                        if (p != dnode->first_free) {
 247                                hpfs_error(s, "size on last dirent does not match first_free; dnode %08x", secno);
 248                                goto bail;
 249                        }
 250                        if (d[pp + 30] != 1 || d[pp + 31] != 255) {
 251                                hpfs_error(s, "dnode %08x does not end with \\377 entry", secno);
 252                                goto bail;
 253                        }
 254                        if (b == 3) printk("HPFS: warning: unbalanced dnode tree, dnode %08x; see hpfs.txt 4 more info\n", secno);
 255                }
 256        return dnode;
 257        bail:
 258        hpfs_brelse4(qbh);
 259        return NULL;
 260}
 261
 262dnode_secno hpfs_fnode_dno(struct super_block *s, ino_t ino)
 263{
 264        struct buffer_head *bh;
 265        struct fnode *fnode;
 266        dnode_secno dno;
 267
 268        fnode = hpfs_map_fnode(s, ino, &bh);
 269        if (!fnode)
 270                return 0;
 271
 272        dno = fnode->u.external[0].disk_secno;
 273        brelse(bh);
 274        return dno;
 275}
 276
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