dir.c

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/*
 * dir.c
 *
 * PURPOSE
 *  Directory handling routines for the OSTA-UDF(tm) filesystem.
 *
 * COPYRIGHT
 *  This file is distributed under the terms of the GNU General Public
 *  License (GPL). Copies of the GPL can be obtained from:
 *      ftp://prep.ai.mit.edu/pub/gnu/GPL
 *  Each contributing author retains all rights to their own work.
 *
 *  (C) 1998-2004 Ben Fennema
 *
 * HISTORY
 *
 *  10/05/98 dgb  Split directory operations into its own file
 *                Implemented directory reads via do_udf_readdir
 *  10/06/98      Made directory operations work!
 *  11/17/98      Rewrote directory to support ICBTAG_FLAG_AD_LONG
 *  11/25/98 blf  Rewrote directory handling (readdir+lookup) to support reading
 *                across blocks.
 *  12/12/98      Split out the lookup code to namei.c. bulk of directory
 *                code now in directory.c:udf_fileident_read.
 */

#include "udfdecl.h"

#include <linux/string.h>
#include <linux/errno.h>
#include <linux/mm.h>
#include <linux/slab.h>
#include <linux/buffer_head.h>

#include "udf_i.h"
#include "udf_sb.h"

static int do_udf_readdir(struct inode *dir, struct file *filp,
              filldir_t filldir, void *dirent)
{
    struct udf_fileident_bh fibh = { .sbh = NULL, .ebh = NULL};
    struct fileIdentDesc *fi = NULL;
    struct fileIdentDesc cfi;
    int block, iblock;
    loff_t nf_pos = (filp->f_pos - 1) << 2;
    int flen;
    unsigned char *fname = NULL;
    unsigned char *nameptr;
    uint16_t liu;
    uint8_t lfi;
    loff_t size = udf_ext0_offset(dir) + dir->i_size;
    struct buffer_head *tmp, *bha[16];
    struct kernel_lb_addr eloc;
    uint32_t elen;
    sector_t offset;
    int i, num, ret = 0;
    unsigned int dt_type;
    struct extent_position epos = { NULL, 0, {0, 0} };
    struct udf_inode_info *iinfo;

    if (nf_pos >= size)
        goto out;

    fname = kmalloc(UDF_NAME_LEN, GFP_NOFS);
    if (!fname) {
        ret = -ENOMEM;
        goto out;
    }

    if (nf_pos == 0)
        nf_pos = udf_ext0_offset(dir);

    fibh.soffset = fibh.eoffset = nf_pos & (dir->i_sb->s_blocksize - 1);
    iinfo = UDF_I(dir);
    if (iinfo->i_alloc_type != ICBTAG_FLAG_AD_IN_ICB) {
        if (inode_bmap(dir, nf_pos >> dir->i_sb->s_blocksize_bits,
            &epos, &eloc, &elen, &offset)
            != (EXT_RECORDED_ALLOCATED >> 30)) {
            ret = -ENOENT;
            goto out;
        }
        block = udf_get_lb_pblock(dir->i_sb, &eloc, offset);
        if ((++offset << dir->i_sb->s_blocksize_bits) < elen) {
            if (iinfo->i_alloc_type == ICBTAG_FLAG_AD_SHORT)
                epos.offset -= sizeof(struct short_ad);
            else if (iinfo->i_alloc_type ==
                    ICBTAG_FLAG_AD_LONG)
                epos.offset -= sizeof(struct long_ad);
        } else {
            offset = 0;
        }

        if (!(fibh.sbh = fibh.ebh = udf_tread(dir->i_sb, block))) {
            ret = -EIO;
            goto out;
        }

        if (!(offset & ((16 >> (dir->i_sb->s_blocksize_bits - 9)) - 1))) {
            i = 16 >> (dir->i_sb->s_blocksize_bits - 9);
            if (i + offset > (elen >> dir->i_sb->s_blocksize_bits))
                i = (elen >> dir->i_sb->s_blocksize_bits) - offset;
            for (num = 0; i > 0; i--) {
                block = udf_get_lb_pblock(dir->i_sb, &eloc, offset + i);
                tmp = udf_tgetblk(dir->i_sb, block);
                if (tmp && !buffer_uptodate(tmp) && !buffer_locked(tmp))
                    bha[num++] = tmp;
                else
                    brelse(tmp);
            }
            if (num) {
                ll_rw_block(READA, num, bha);
                for (i = 0; i < num; i++)
                    brelse(bha[i]);
            }
        }
    }

    while (nf_pos < size) {
        filp->f_pos = (nf_pos >> 2) + 1;

        fi = udf_fileident_read(dir, &nf_pos, &fibh, &cfi, &epos, &eloc,
                    &elen, &offset);
        if (!fi)
            goto out;

        liu = le16_to_cpu(cfi.lengthOfImpUse);
        lfi = cfi.lengthFileIdent;

        if (fibh.sbh == fibh.ebh) {
            nameptr = fi->fileIdent + liu;
        } else {
            int poffset;    /* Unpaded ending offset */

            poffset = fibh.soffset + sizeof(struct fileIdentDesc) + liu + lfi;

            if (poffset >= lfi) {
                nameptr = (char *)(fibh.ebh->b_data + poffset - lfi);
            } else {
                nameptr = fname;
                memcpy(nameptr, fi->fileIdent + liu,
                       lfi - poffset);
                memcpy(nameptr + lfi - poffset,
                       fibh.ebh->b_data, poffset);
            }
        }

        if ((cfi.fileCharacteristics & FID_FILE_CHAR_DELETED) != 0) {
            if (!UDF_QUERY_FLAG(dir->i_sb, UDF_FLAG_UNDELETE))
                continue;
        }

        if ((cfi.fileCharacteristics & FID_FILE_CHAR_HIDDEN) != 0) {
            if (!UDF_QUERY_FLAG(dir->i_sb, UDF_FLAG_UNHIDE))
                continue;
        }

        if (cfi.fileCharacteristics & FID_FILE_CHAR_PARENT) {
            iblock = parent_ino(filp->f_path.dentry);
            flen = 2;
            memcpy(fname, "..", flen);
            dt_type = DT_DIR;
        } else {
            struct kernel_lb_addr tloc = lelb_to_cpu(cfi.icb.extLocation);

            iblock = udf_get_lb_pblock(dir->i_sb, &tloc, 0);
            flen = udf_get_filename(dir->i_sb, nameptr, fname, lfi);
            dt_type = DT_UNKNOWN;
        }

        if (flen && filldir(dirent, fname, flen, filp->f_pos,
                    iblock, dt_type) < 0)
            goto out;
    } /* end while */

    filp->f_pos = (nf_pos >> 2) + 1;

out:
    if (fibh.sbh != fibh.ebh)
        brelse(fibh.ebh);
    brelse(fibh.sbh);
    brelse(epos.bh);
    kfree(fname);

    return ret;
}

static int udf_readdir(struct file *filp, void *dirent, filldir_t filldir)
{
    struct inode *dir = filp->f_path.dentry->d_inode;
    int result;

    if (filp->f_pos == 0) {
        if (filldir(dirent, ".", 1, filp->f_pos, dir->i_ino, DT_DIR) < 0) {
            return 0;
        }
        filp->f_pos++;
    }

    result = do_udf_readdir(dir, filp, filldir, dirent);
    return result;
}

/* readdir and lookup functions */
const struct file_operations udf_dir_operations = {
    .llseek         = generic_file_llseek,
    .read           = generic_read_dir,
    .readdir        = udf_readdir,
    .unlocked_ioctl     = udf_ioctl,
    .fsync          = generic_file_fsync,
};