linux/fs/udf/dir.c
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   1/*
   2 * dir.c
   3 *
   4 * PURPOSE
   5 *  Directory handling routines for the OSTA-UDF(tm) filesystem.
   6 *
   7 * COPYRIGHT
   8 *      This file is distributed under the terms of the GNU General Public
   9 *      License (GPL). Copies of the GPL can be obtained from:
  10 *              ftp://prep.ai.mit.edu/pub/gnu/GPL
  11 *      Each contributing author retains all rights to their own work.
  12 *
  13 *  (C) 1998-2004 Ben Fennema
  14 *
  15 * HISTORY
  16 *
  17 *  10/05/98 dgb  Split directory operations into its own file
  18 *                Implemented directory reads via do_udf_readdir
  19 *  10/06/98      Made directory operations work!
  20 *  11/17/98      Rewrote directory to support ICBTAG_FLAG_AD_LONG
  21 *  11/25/98 blf  Rewrote directory handling (readdir+lookup) to support reading
  22 *                across blocks.
  23 *  12/12/98      Split out the lookup code to namei.c. bulk of directory
  24 *                code now in directory.c:udf_fileident_read.
  25 */
  26
  27#include "udfdecl.h"
  28
  29#include <linux/string.h>
  30#include <linux/errno.h>
  31#include <linux/mm.h>
  32#include <linux/slab.h>
  33#include <linux/buffer_head.h>
  34
  35#include "udf_i.h"
  36#include "udf_sb.h"
  37
  38
  39static int udf_readdir(struct file *file, struct dir_context *ctx)
  40{
  41        struct inode *dir = file_inode(file);
  42        struct udf_inode_info *iinfo = UDF_I(dir);
  43        struct udf_fileident_bh fibh = { .sbh = NULL, .ebh = NULL};
  44        struct fileIdentDesc *fi = NULL;
  45        struct fileIdentDesc cfi;
  46        int block, iblock;
  47        loff_t nf_pos;
  48        int flen;
  49        unsigned char *fname = NULL;
  50        unsigned char *nameptr;
  51        uint16_t liu;
  52        uint8_t lfi;
  53        loff_t size = udf_ext0_offset(dir) + dir->i_size;
  54        struct buffer_head *tmp, *bha[16];
  55        struct kernel_lb_addr eloc;
  56        uint32_t elen;
  57        sector_t offset;
  58        int i, num, ret = 0;
  59        struct extent_position epos = { NULL, 0, {0, 0} };
  60
  61        if (ctx->pos == 0) {
  62                if (!dir_emit_dot(file, ctx))
  63                        return 0;
  64                ctx->pos = 1;
  65        }
  66        nf_pos = (ctx->pos - 1) << 2;
  67        if (nf_pos >= size)
  68                goto out;
  69
  70        fname = kmalloc(UDF_NAME_LEN, GFP_NOFS);
  71        if (!fname) {
  72                ret = -ENOMEM;
  73                goto out;
  74        }
  75
  76        if (nf_pos == 0)
  77                nf_pos = udf_ext0_offset(dir);
  78
  79        fibh.soffset = fibh.eoffset = nf_pos & (dir->i_sb->s_blocksize - 1);
  80        if (iinfo->i_alloc_type != ICBTAG_FLAG_AD_IN_ICB) {
  81                if (inode_bmap(dir, nf_pos >> dir->i_sb->s_blocksize_bits,
  82                    &epos, &eloc, &elen, &offset)
  83                    != (EXT_RECORDED_ALLOCATED >> 30)) {
  84                        ret = -ENOENT;
  85                        goto out;
  86                }
  87                block = udf_get_lb_pblock(dir->i_sb, &eloc, offset);
  88                if ((++offset << dir->i_sb->s_blocksize_bits) < elen) {
  89                        if (iinfo->i_alloc_type == ICBTAG_FLAG_AD_SHORT)
  90                                epos.offset -= sizeof(struct short_ad);
  91                        else if (iinfo->i_alloc_type ==
  92                                        ICBTAG_FLAG_AD_LONG)
  93                                epos.offset -= sizeof(struct long_ad);
  94                } else {
  95                        offset = 0;
  96                }
  97
  98                if (!(fibh.sbh = fibh.ebh = udf_tread(dir->i_sb, block))) {
  99                        ret = -EIO;
 100                        goto out;
 101                }
 102
 103                if (!(offset & ((16 >> (dir->i_sb->s_blocksize_bits - 9)) - 1))) {
 104                        i = 16 >> (dir->i_sb->s_blocksize_bits - 9);
 105                        if (i + offset > (elen >> dir->i_sb->s_blocksize_bits))
 106                                i = (elen >> dir->i_sb->s_blocksize_bits) - offset;
 107                        for (num = 0; i > 0; i--) {
 108                                block = udf_get_lb_pblock(dir->i_sb, &eloc, offset + i);
 109                                tmp = udf_tgetblk(dir->i_sb, block);
 110                                if (tmp && !buffer_uptodate(tmp) && !buffer_locked(tmp))
 111                                        bha[num++] = tmp;
 112                                else
 113                                        brelse(tmp);
 114                        }
 115                        if (num) {
 116                                ll_rw_block(READA, num, bha);
 117                                for (i = 0; i < num; i++)
 118                                        brelse(bha[i]);
 119                        }
 120                }
 121        }
 122
 123        while (nf_pos < size) {
 124                struct kernel_lb_addr tloc;
 125
 126                ctx->pos = (nf_pos >> 2) + 1;
 127
 128                fi = udf_fileident_read(dir, &nf_pos, &fibh, &cfi, &epos, &eloc,
 129                                        &elen, &offset);
 130                if (!fi)
 131                        goto out;
 132
 133                liu = le16_to_cpu(cfi.lengthOfImpUse);
 134                lfi = cfi.lengthFileIdent;
 135
 136                if (fibh.sbh == fibh.ebh) {
 137                        nameptr = fi->fileIdent + liu;
 138                } else {
 139                        int poffset;    /* Unpaded ending offset */
 140
 141                        poffset = fibh.soffset + sizeof(struct fileIdentDesc) + liu + lfi;
 142
 143                        if (poffset >= lfi) {
 144                                nameptr = (char *)(fibh.ebh->b_data + poffset - lfi);
 145                        } else {
 146                                nameptr = fname;
 147                                memcpy(nameptr, fi->fileIdent + liu,
 148                                       lfi - poffset);
 149                                memcpy(nameptr + lfi - poffset,
 150                                       fibh.ebh->b_data, poffset);
 151                        }
 152                }
 153
 154                if ((cfi.fileCharacteristics & FID_FILE_CHAR_DELETED) != 0) {
 155                        if (!UDF_QUERY_FLAG(dir->i_sb, UDF_FLAG_UNDELETE))
 156                                continue;
 157                }
 158
 159                if ((cfi.fileCharacteristics & FID_FILE_CHAR_HIDDEN) != 0) {
 160                        if (!UDF_QUERY_FLAG(dir->i_sb, UDF_FLAG_UNHIDE))
 161                                continue;
 162                }
 163
 164                if (cfi.fileCharacteristics & FID_FILE_CHAR_PARENT) {
 165                        if (!dir_emit_dotdot(file, ctx))
 166                                goto out;
 167                        continue;
 168                }
 169
 170                flen = udf_get_filename(dir->i_sb, nameptr, fname, lfi);
 171                if (!flen)
 172                        continue;
 173
 174                tloc = lelb_to_cpu(cfi.icb.extLocation);
 175                iblock = udf_get_lb_pblock(dir->i_sb, &tloc, 0);
 176                if (!dir_emit(ctx, fname, flen, iblock, DT_UNKNOWN))
 177                        goto out;
 178        } /* end while */
 179
 180        ctx->pos = (nf_pos >> 2) + 1;
 181
 182out:
 183        if (fibh.sbh != fibh.ebh)
 184                brelse(fibh.ebh);
 185        brelse(fibh.sbh);
 186        brelse(epos.bh);
 187        kfree(fname);
 188
 189        return ret;
 190}
 191
 192/* readdir and lookup functions */
 193const struct file_operations udf_dir_operations = {
 194        .llseek                 = generic_file_llseek,
 195        .read                   = generic_read_dir,
 196        .iterate                = udf_readdir,
 197        .unlocked_ioctl         = udf_ioctl,
 198        .fsync                  = generic_file_fsync,
 199};
 200
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