directory.c

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/*
 * directory.c
 *
 * PURPOSE
 *  Directory related functions
 *
 * 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.
 */

#include "udfdecl.h"
#include "udf_i.h"

#include <linux/fs.h>
#include <linux/string.h>
#include <linux/buffer_head.h>

struct fileIdentDesc *udf_fileident_read(struct inode *dir, loff_t *nf_pos,
                     struct udf_fileident_bh *fibh,
                     struct fileIdentDesc *cfi,
                     struct extent_position *epos,
                     struct kernel_lb_addr *eloc, uint32_t *elen,
                     sector_t *offset)
{
    struct fileIdentDesc *fi;
    int i, num, block;
    struct buffer_head *tmp, *bha[16];
    struct udf_inode_info *iinfo = UDF_I(dir);

    fibh->soffset = fibh->eoffset;

    if (iinfo->i_alloc_type == ICBTAG_FLAG_AD_IN_ICB) {
        fi = udf_get_fileident(iinfo->i_ext.i_data -
                       (iinfo->i_efe ?
                    sizeof(struct extendedFileEntry) :
                    sizeof(struct fileEntry)),
                       dir->i_sb->s_blocksize,
                       &(fibh->eoffset));
        if (!fi)
            return NULL;

        *nf_pos += fibh->eoffset - fibh->soffset;

        memcpy((uint8_t *)cfi, (uint8_t *)fi,
               sizeof(struct fileIdentDesc));

        return fi;
    }

    if (fibh->eoffset == dir->i_sb->s_blocksize) {
        int lextoffset = epos->offset;
        unsigned char blocksize_bits = dir->i_sb->s_blocksize_bits;

        if (udf_next_aext(dir, epos, eloc, elen, 1) !=
            (EXT_RECORDED_ALLOCATED >> 30))
            return NULL;

        block = udf_get_lb_pblock(dir->i_sb, eloc, *offset);

        (*offset)++;

        if ((*offset << blocksize_bits) >= *elen)
            *offset = 0;
        else
            epos->offset = lextoffset;

        brelse(fibh->sbh);
        fibh->sbh = fibh->ebh = udf_tread(dir->i_sb, block);
        if (!fibh->sbh)
            return NULL;
        fibh->soffset = fibh->eoffset = 0;

        if (!(*offset & ((16 >> (blocksize_bits - 9)) - 1))) {
            i = 16 >> (blocksize_bits - 9);
            if (i + *offset > (*elen >> blocksize_bits))
                i = (*elen >> 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]);
            }
        }
    } else if (fibh->sbh != fibh->ebh) {
        brelse(fibh->sbh);
        fibh->sbh = fibh->ebh;
    }

    fi = udf_get_fileident(fibh->sbh->b_data, dir->i_sb->s_blocksize,
                   &(fibh->eoffset));

    if (!fi)
        return NULL;

    *nf_pos += fibh->eoffset - fibh->soffset;

    if (fibh->eoffset <= dir->i_sb->s_blocksize) {
        memcpy((uint8_t *)cfi, (uint8_t *)fi,
               sizeof(struct fileIdentDesc));
    } else if (fibh->eoffset > dir->i_sb->s_blocksize) {
        int lextoffset = epos->offset;

        if (udf_next_aext(dir, epos, eloc, elen, 1) !=
            (EXT_RECORDED_ALLOCATED >> 30))
            return NULL;

        block = udf_get_lb_pblock(dir->i_sb, eloc, *offset);

        (*offset)++;

        if ((*offset << dir->i_sb->s_blocksize_bits) >= *elen)
            *offset = 0;
        else
            epos->offset = lextoffset;

        fibh->soffset -= dir->i_sb->s_blocksize;
        fibh->eoffset -= dir->i_sb->s_blocksize;

        fibh->ebh = udf_tread(dir->i_sb, block);
        if (!fibh->ebh)
            return NULL;

        if (sizeof(struct fileIdentDesc) > -fibh->soffset) {
            int fi_len;

            memcpy((uint8_t *)cfi, (uint8_t *)fi, -fibh->soffset);
            memcpy((uint8_t *)cfi - fibh->soffset,
                   fibh->ebh->b_data,
                   sizeof(struct fileIdentDesc) + fibh->soffset);

            fi_len = (sizeof(struct fileIdentDesc) +
                  cfi->lengthFileIdent +
                  le16_to_cpu(cfi->lengthOfImpUse) + 3) & ~3;

            *nf_pos += fi_len - (fibh->eoffset - fibh->soffset);
            fibh->eoffset = fibh->soffset + fi_len;
        } else {
            memcpy((uint8_t *)cfi, (uint8_t *)fi,
                   sizeof(struct fileIdentDesc));
        }
    }
    return fi;
}

struct fileIdentDesc *udf_get_fileident(void *buffer, int bufsize, int *offset)
{
    struct fileIdentDesc *fi;
    int lengthThisIdent;
    uint8_t *ptr;
    int padlen;

    if ((!buffer) || (!offset)) {
        udf_debug("invalidparms, buffer=%p, offset=%p\n",
              buffer, offset);
        return NULL;
    }

    ptr = buffer;

    if ((*offset > 0) && (*offset < bufsize))
        ptr += *offset;
    fi = (struct fileIdentDesc *)ptr;
    if (fi->descTag.tagIdent != cpu_to_le16(TAG_IDENT_FID)) {
        udf_debug("0x%x != TAG_IDENT_FID\n",
              le16_to_cpu(fi->descTag.tagIdent));
        udf_debug("offset: %u sizeof: %lu bufsize: %u\n",
              *offset, (unsigned long)sizeof(struct fileIdentDesc),
              bufsize);
        return NULL;
    }
    if ((*offset + sizeof(struct fileIdentDesc)) > bufsize)
        lengthThisIdent = sizeof(struct fileIdentDesc);
    else
        lengthThisIdent = sizeof(struct fileIdentDesc) +
            fi->lengthFileIdent + le16_to_cpu(fi->lengthOfImpUse);

    /* we need to figure padding, too! */
    padlen = lengthThisIdent % UDF_NAME_PAD;
    if (padlen)
        lengthThisIdent += (UDF_NAME_PAD - padlen);
    *offset = *offset + lengthThisIdent;

    return fi;
}

struct short_ad *udf_get_fileshortad(uint8_t *ptr, int maxoffset, uint32_t *offset,
                  int inc)
{
    struct short_ad *sa;

    if ((!ptr) || (!offset)) {
        pr_err("%s: invalidparms\n", __func__);
        return NULL;
    }

    if ((*offset + sizeof(struct short_ad)) > maxoffset)
        return NULL;
    else {
        sa = (struct short_ad *)ptr;
        if (sa->extLength == 0)
            return NULL;
    }

    if (inc)
        *offset += sizeof(struct short_ad);
    return sa;
}

struct long_ad *udf_get_filelongad(uint8_t *ptr, int maxoffset, uint32_t *offset, int inc)
{
    struct long_ad *la;

    if ((!ptr) || (!offset)) {
        pr_err("%s: invalidparms\n", __func__);
        return NULL;
    }

    if ((*offset + sizeof(struct long_ad)) > maxoffset)
        return NULL;
    else {
        la = (struct long_ad *)ptr;
        if (la->extLength == 0)
            return NULL;
    }

    if (inc)
        *offset += sizeof(struct long_ad);
    return la;
}