map.c

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/*
 *  linux/fs/hpfs/map.c
 *
 *  Mikulas Patocka ([email protected]), 1998-1999
 *
 *  mapping structures to memory with some minimal checks
 */

#include "hpfs_fn.h"

__le32 *hpfs_map_dnode_bitmap(struct super_block *s, struct quad_buffer_head *qbh)
{
    return hpfs_map_4sectors(s, hpfs_sb(s)->sb_dmap, qbh, 0);
}

__le32 *hpfs_map_bitmap(struct super_block *s, unsigned bmp_block,
             struct quad_buffer_head *qbh, char *id)
{
    secno sec;
    if (hpfs_sb(s)->sb_chk) if (bmp_block * 16384 > hpfs_sb(s)->sb_fs_size) {
        hpfs_error(s, "hpfs_map_bitmap called with bad parameter: %08x at %s", bmp_block, id);
        return NULL;
    }
    sec = le32_to_cpu(hpfs_sb(s)->sb_bmp_dir[bmp_block]);
    if (!sec || sec > hpfs_sb(s)->sb_fs_size-4) {
        hpfs_error(s, "invalid bitmap block pointer %08x -> %08x at %s", bmp_block, sec, id);
        return NULL;
    }
    return hpfs_map_4sectors(s, sec, qbh, 4);
}

/*
 * Load first code page into kernel memory, return pointer to 256-byte array,
 * first 128 bytes are uppercasing table for chars 128-255, next 128 bytes are
 * lowercasing table
 */

unsigned char *hpfs_load_code_page(struct super_block *s, secno cps)
{
    struct buffer_head *bh;
    secno cpds;
    unsigned cpi;
    unsigned char *ptr;
    unsigned char *cp_table;
    int i;
    struct code_page_data *cpd;
    struct code_page_directory *cp = hpfs_map_sector(s, cps, &bh, 0);
    if (!cp) return NULL;
    if (le32_to_cpu(cp->magic) != CP_DIR_MAGIC) {
        printk("HPFS: Code page directory magic doesn't match (magic = %08x)\n", le32_to_cpu(cp->magic));
        brelse(bh);
        return NULL;
    }
    if (!le32_to_cpu(cp->n_code_pages)) {
        printk("HPFS: n_code_pages == 0\n");
        brelse(bh);
        return NULL;
    }
    cpds = le32_to_cpu(cp->array[0].code_page_data);
    cpi = le16_to_cpu(cp->array[0].index);
    brelse(bh);

    if (cpi >= 3) {
        printk("HPFS: Code page index out of array\n");
        return NULL;
    }
    
    if (!(cpd = hpfs_map_sector(s, cpds, &bh, 0))) return NULL;
    if (le16_to_cpu(cpd->offs[cpi]) > 0x178) {
        printk("HPFS: Code page index out of sector\n");
        brelse(bh);
        return NULL;
    }
    ptr = (unsigned char *)cpd + le16_to_cpu(cpd->offs[cpi]) + 6;
    if (!(cp_table = kmalloc(256, GFP_KERNEL))) {
        printk("HPFS: out of memory for code page table\n");
        brelse(bh);
        return NULL;
    }
    memcpy(cp_table, ptr, 128);
    brelse(bh);

    /* Try to build lowercasing table from uppercasing one */

    for (i=128; i<256; i++) cp_table[i]=i;
    for (i=128; i<256; i++) if (cp_table[i-128]!=i && cp_table[i-128]>=128)
        cp_table[cp_table[i-128]] = i;
    
    return cp_table;
}

__le32 *hpfs_load_bitmap_directory(struct super_block *s, secno bmp)
{
    struct buffer_head *bh;
    int n = (hpfs_sb(s)->sb_fs_size + 0x200000 - 1) >> 21;
    int i;
    __le32 *b;
    if (!(b = kmalloc(n * 512, GFP_KERNEL))) {
        printk("HPFS: can't allocate memory for bitmap directory\n");
        return NULL;
    }   
    for (i=0;i<n;i++) {
        __le32 *d = hpfs_map_sector(s, bmp+i, &bh, n - i - 1);
        if (!d) {
            kfree(b);
            return NULL;
        }
        memcpy((char *)b + 512 * i, d, 512);
        brelse(bh);
    }
    return b;
}

/*
 * Load fnode to memory
 */

struct fnode *hpfs_map_fnode(struct super_block *s, ino_t ino, struct buffer_head **bhp)
{
    struct fnode *fnode;
    if (hpfs_sb(s)->sb_chk) if (hpfs_chk_sectors(s, ino, 1, "fnode")) {
        return NULL;
    }
    if ((fnode = hpfs_map_sector(s, ino, bhp, FNODE_RD_AHEAD))) {
        if (hpfs_sb(s)->sb_chk) {
            struct extended_attribute *ea;
            struct extended_attribute *ea_end;
            if (le32_to_cpu(fnode->magic) != FNODE_MAGIC) {
                hpfs_error(s, "bad magic on fnode %08lx",
                    (unsigned long)ino);
                goto bail;
            }
            if (!fnode_is_dir(fnode)) {
                if ((unsigned)fnode->btree.n_used_nodes + (unsigned)fnode->btree.n_free_nodes !=
                    (bp_internal(&fnode->btree) ? 12 : 8)) {
                    hpfs_error(s,
                       "bad number of nodes in fnode %08lx",
                        (unsigned long)ino);
                    goto bail;
                }
                if (le16_to_cpu(fnode->btree.first_free) !=
                    8 + fnode->btree.n_used_nodes * (bp_internal(&fnode->btree) ? 8 : 12)) {
                    hpfs_error(s,
                        "bad first_free pointer in fnode %08lx",
                        (unsigned long)ino);
                    goto bail;
                }
            }
            if (le16_to_cpu(fnode->ea_size_s) && (le16_to_cpu(fnode->ea_offs) < 0xc4 ||
               le16_to_cpu(fnode->ea_offs) + le16_to_cpu(fnode->acl_size_s) + le16_to_cpu(fnode->ea_size_s) > 0x200)) {
                hpfs_error(s,
                    "bad EA info in fnode %08lx: ea_offs == %04x ea_size_s == %04x",
                    (unsigned long)ino,
                    le16_to_cpu(fnode->ea_offs), le16_to_cpu(fnode->ea_size_s));
                goto bail;
            }
            ea = fnode_ea(fnode);
            ea_end = fnode_end_ea(fnode);
            while (ea != ea_end) {
                if (ea > ea_end) {
                    hpfs_error(s, "bad EA in fnode %08lx",
                        (unsigned long)ino);
                    goto bail;
                }
                ea = next_ea(ea);
            }
        }
    }
    return fnode;
    bail:
    brelse(*bhp);
    return NULL;
}

struct anode *hpfs_map_anode(struct super_block *s, anode_secno ano, struct buffer_head **bhp)
{
    struct anode *anode;
    if (hpfs_sb(s)->sb_chk) if (hpfs_chk_sectors(s, ano, 1, "anode")) return NULL;
    if ((anode = hpfs_map_sector(s, ano, bhp, ANODE_RD_AHEAD)))
        if (hpfs_sb(s)->sb_chk) {
            if (le32_to_cpu(anode->magic) != ANODE_MAGIC) {
                hpfs_error(s, "bad magic on anode %08x", ano);
                goto bail;
            }
            if (le32_to_cpu(anode->self) != ano) {
                hpfs_error(s, "self pointer invalid on anode %08x", ano);
                goto bail;
            }
            if ((unsigned)anode->btree.n_used_nodes + (unsigned)anode->btree.n_free_nodes !=
                (bp_internal(&anode->btree) ? 60 : 40)) {
                hpfs_error(s, "bad number of nodes in anode %08x", ano);
                goto bail;
            }
            if (le16_to_cpu(anode->btree.first_free) !=
                8 + anode->btree.n_used_nodes * (bp_internal(&anode->btree) ? 8 : 12)) {
                hpfs_error(s, "bad first_free pointer in anode %08x", ano);
                goto bail;
            }
        }
    return anode;
    bail:
    brelse(*bhp);
    return NULL;
}

/*
 * Load dnode to memory and do some checks
 */

struct dnode *hpfs_map_dnode(struct super_block *s, unsigned secno,
                 struct quad_buffer_head *qbh)
{
    struct dnode *dnode;
    if (hpfs_sb(s)->sb_chk) {
        if (hpfs_chk_sectors(s, secno, 4, "dnode")) return NULL;
        if (secno & 3) {
            hpfs_error(s, "dnode %08x not byte-aligned", secno);
            return NULL;
        }   
    }
    if ((dnode = hpfs_map_4sectors(s, secno, qbh, DNODE_RD_AHEAD)))
        if (hpfs_sb(s)->sb_chk) {
            unsigned p, pp = 0;
            unsigned char *d = (unsigned char *)dnode;
            int b = 0;
            if (le32_to_cpu(dnode->magic) != DNODE_MAGIC) {
                hpfs_error(s, "bad magic on dnode %08x", secno);
                goto bail;
            }
            if (le32_to_cpu(dnode->self) != secno)
                hpfs_error(s, "bad self pointer on dnode %08x self = %08x", secno, le32_to_cpu(dnode->self));
            /* Check dirents - bad dirents would cause infinite
               loops or shooting to memory */
            if (le32_to_cpu(dnode->first_free) > 2048) {
                hpfs_error(s, "dnode %08x has first_free == %08x", secno, le32_to_cpu(dnode->first_free));
                goto bail;
            }
            for (p = 20; p < le32_to_cpu(dnode->first_free); p += d[p] + (d[p+1] << 8)) {
                struct hpfs_dirent *de = (struct hpfs_dirent *)((char *)dnode + p);
                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) {
                    hpfs_error(s, "bad dirent size in dnode %08x, dirent %03x, last %03x", secno, p, pp);
                    goto bail;
                }
                if (((31 + de->namelen + de->down*4 + 3) & ~3) != le16_to_cpu(de->length)) {
                    if (((31 + de->namelen + de->down*4 + 3) & ~3) < le16_to_cpu(de->length) && s->s_flags & MS_RDONLY) goto ok;
                    hpfs_error(s, "namelen does not match dirent size in dnode %08x, dirent %03x, last %03x", secno, p, pp);
                    goto bail;
                }
                ok:
                if (hpfs_sb(s)->sb_chk >= 2) b |= 1 << de->down;
                if (de->down) if (de_down_pointer(de) < 0x10) {
                    hpfs_error(s, "bad down pointer in dnode %08x, dirent %03x, last %03x", secno, p, pp);
                    goto bail;
                }
                pp = p;
                
            }
            if (p != le32_to_cpu(dnode->first_free)) {
                hpfs_error(s, "size on last dirent does not match first_free; dnode %08x", secno);
                goto bail;
            }
            if (d[pp + 30] != 1 || d[pp + 31] != 255) {
                hpfs_error(s, "dnode %08x does not end with \\377 entry", secno);
                goto bail;
            }
            if (b == 3) printk("HPFS: warning: unbalanced dnode tree, dnode %08x; see hpfs.txt 4 more info\n", secno);
        }
    return dnode;
    bail:
    hpfs_brelse4(qbh);
    return NULL;
}

dnode_secno hpfs_fnode_dno(struct super_block *s, ino_t ino)
{
    struct buffer_head *bh;
    struct fnode *fnode;
    dnode_secno dno;

    fnode = hpfs_map_fnode(s, ino, &bh);
    if (!fnode)
        return 0;

    dno = le32_to_cpu(fnode->u.external[0].disk_secno);
    brelse(bh);
    return dno;
}