dir.c

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/*
 *  linux/fs/isofs/dir.c
 *
 *  (C) 1992, 1993, 1994  Eric Youngdale Modified for ISO 9660 filesystem.
 *
 *  (C) 1991  Linus Torvalds - minix filesystem
 *
 *  Steve Beynon               : Missing last directory entries fixed
 *  ([email protected])      : 21st June 1996
 *
 *  isofs directory handling functions
 */
#include <linux/gfp.h>
#include "isofs.h"

int isofs_name_translate(struct iso_directory_record *de, char *new, struct inode *inode)
{
    char * old = de->name;
    int len = de->name_len[0];
    int i;

    for (i = 0; i < len; i++) {
        unsigned char c = old[i];
        if (!c)
            break;

        if (c >= 'A' && c <= 'Z')
            c |= 0x20;  /* lower case */

        /* Drop trailing '.;1' (ISO 9660:1988 7.5.1 requires period) */
        if (c == '.' && i == len - 3 && old[i + 1] == ';' && old[i + 2] == '1')
            break;

        /* Drop trailing ';1' */
        if (c == ';' && i == len - 2 && old[i + 1] == '1')
            break;

        /* Convert remaining ';' to '.' */
        /* Also '/' to '.' (broken Acorn-generated ISO9660 images) */
        if (c == ';' || c == '/')
            c = '.';

        new[i] = c;
    }
    return i;
}

/* Acorn extensions written by Matthew Wilcox <[email protected]> 1998 */
int get_acorn_filename(struct iso_directory_record *de,
                char *retname, struct inode *inode)
{
    int std;
    unsigned char *chr;
    int retnamlen = isofs_name_translate(de, retname, inode);

    if (retnamlen == 0)
        return 0;
    std = sizeof(struct iso_directory_record) + de->name_len[0];
    if (std & 1)
        std++;
    if ((*((unsigned char *) de) - std) != 32)
        return retnamlen;
    chr = ((unsigned char *) de) + std;
    if (strncmp(chr, "ARCHIMEDES", 10))
        return retnamlen;
    if ((*retname == '_') && ((chr[19] & 1) == 1))
        *retname = '!';
    if (((de->flags[0] & 2) == 0) && (chr[13] == 0xff)
        && ((chr[12] & 0xf0) == 0xf0)) {
        retname[retnamlen] = ',';
        sprintf(retname+retnamlen+1, "%3.3x",
            ((chr[12] & 0xf) << 8) | chr[11]);
        retnamlen += 4;
    }
    return retnamlen;
}

/*
 * This should _really_ be cleaned up some day..
 */
static int do_isofs_readdir(struct inode *inode, struct file *filp,
        void *dirent, filldir_t filldir,
        char *tmpname, struct iso_directory_record *tmpde)
{
    unsigned long bufsize = ISOFS_BUFFER_SIZE(inode);
    unsigned char bufbits = ISOFS_BUFFER_BITS(inode);
    unsigned long block, offset, block_saved, offset_saved;
    unsigned long inode_number = 0; /* Quiet GCC */
    struct buffer_head *bh = NULL;
    int len;
    int map;
    int first_de = 1;
    char *p = NULL;     /* Quiet GCC */
    struct iso_directory_record *de;
    struct isofs_sb_info *sbi = ISOFS_SB(inode->i_sb);

    offset = filp->f_pos & (bufsize - 1);
    block = filp->f_pos >> bufbits;

    while (filp->f_pos < inode->i_size) {
        int de_len;

        if (!bh) {
            bh = isofs_bread(inode, block);
            if (!bh)
                return 0;
        }

        de = (struct iso_directory_record *) (bh->b_data + offset);

        de_len = *(unsigned char *) de;

        /*
         * If the length byte is zero, we should move on to the next
         * CDROM sector.  If we are at the end of the directory, we
         * kick out of the while loop.
         */

        if (de_len == 0) {
            brelse(bh);
            bh = NULL;
            filp->f_pos = (filp->f_pos + ISOFS_BLOCK_SIZE) & ~(ISOFS_BLOCK_SIZE - 1);
            block = filp->f_pos >> bufbits;
            offset = 0;
            continue;
        }

        block_saved = block;
        offset_saved = offset;
        offset += de_len;

        /* Make sure we have a full directory entry */
        if (offset >= bufsize) {
            int slop = bufsize - offset + de_len;
            memcpy(tmpde, de, slop);
            offset &= bufsize - 1;
            block++;
            brelse(bh);
            bh = NULL;
            if (offset) {
                bh = isofs_bread(inode, block);
                if (!bh)
                    return 0;
                memcpy((void *) tmpde + slop, bh->b_data, offset);
            }
            de = tmpde;
        }
        /* Basic sanity check, whether name doesn't exceed dir entry */
        if (de_len < de->name_len[0] +
                    sizeof(struct iso_directory_record)) {
            printk(KERN_NOTICE "iso9660: Corrupted directory entry"
                   " in block %lu of inode %lu\n", block,
                   inode->i_ino);
            return -EIO;
        }

        if (first_de) {
            isofs_normalize_block_and_offset(de,
                            &block_saved,
                            &offset_saved);
            inode_number = isofs_get_ino(block_saved,
                            offset_saved, bufbits);
        }

        if (de->flags[-sbi->s_high_sierra] & 0x80) {
            first_de = 0;
            filp->f_pos += de_len;
            continue;
        }
        first_de = 1;

        /* Handle the case of the '.' directory */
        if (de->name_len[0] == 1 && de->name[0] == 0) {
            if (filldir(dirent, ".", 1, filp->f_pos, inode->i_ino, DT_DIR) < 0)
                break;
            filp->f_pos += de_len;
            continue;
        }

        len = 0;

        /* Handle the case of the '..' directory */
        if (de->name_len[0] == 1 && de->name[0] == 1) {
            inode_number = parent_ino(filp->f_path.dentry);
            if (filldir(dirent, "..", 2, filp->f_pos, inode_number, DT_DIR) < 0)
                break;
            filp->f_pos += de_len;
            continue;
        }

        /* Handle everything else.  Do name translation if there
           is no Rock Ridge NM field. */

        /*
         * Do not report hidden files if so instructed, or associated
         * files unless instructed to do so
         */
        if ((sbi->s_hide && (de->flags[-sbi->s_high_sierra] & 1)) ||
            (!sbi->s_showassoc &&
                (de->flags[-sbi->s_high_sierra] & 4))) {
            filp->f_pos += de_len;
            continue;
        }

        map = 1;
        if (sbi->s_rock) {
            len = get_rock_ridge_filename(de, tmpname, inode);
            if (len != 0) {     /* may be -1 */
                p = tmpname;
                map = 0;
            }
        }
        if (map) {
#ifdef CONFIG_JOLIET
            if (sbi->s_joliet_level) {
                len = get_joliet_filename(de, tmpname, inode);
                p = tmpname;
            } else
#endif
            if (sbi->s_mapping == 'a') {
                len = get_acorn_filename(de, tmpname, inode);
                p = tmpname;
            } else
            if (sbi->s_mapping == 'n') {
                len = isofs_name_translate(de, tmpname, inode);
                p = tmpname;
            } else {
                p = de->name;
                len = de->name_len[0];
            }
        }
        if (len > 0) {
            if (filldir(dirent, p, len, filp->f_pos, inode_number, DT_UNKNOWN) < 0)
                break;
        }
        filp->f_pos += de_len;

        continue;
    }
    if (bh)
        brelse(bh);
    return 0;
}

/*
 * Handle allocation of temporary space for name translation and
 * handling split directory entries.. The real work is done by
 * "do_isofs_readdir()".
 */
static int isofs_readdir(struct file *filp,
        void *dirent, filldir_t filldir)
{
    int result;
    char *tmpname;
    struct iso_directory_record *tmpde;
    struct inode *inode = filp->f_path.dentry->d_inode;

    tmpname = (char *)__get_free_page(GFP_KERNEL);
    if (tmpname == NULL)
        return -ENOMEM;

    tmpde = (struct iso_directory_record *) (tmpname+1024);

    result = do_isofs_readdir(inode, filp, dirent, filldir, tmpname, tmpde);

    free_page((unsigned long) tmpname);
    return result;
}

const struct file_operations isofs_dir_operations =
{
    .llseek = generic_file_llseek,
    .read = generic_read_dir,
    .readdir = isofs_readdir,
};

/*
 * directories can handle most operations...
 */
const struct inode_operations isofs_dir_inode_operations =
{
    .lookup = isofs_lookup,
};