fs/adfs/dir_fplus.c

   1 /*
   2  *  linux/fs/adfs/dir_fplus.c
   3  *
   4  *  Copyright (C) 1997-1999 Russell King
   5  *
   6  * This program is free software; you can redistribute it and/or modify
   7  * it under the terms of the GNU General Public License version 2 as
   8  * published by the Free Software Foundation.
   9  */
  10 #include <linux/errno.h>
  11 #include <linux/fs.h>
  12 #include <linux/adfs_fs.h>
  13 #include <linux/time.h>
  14 #include <linux/stat.h>
  15 #include <linux/spinlock.h>
  16 #include <linux/buffer_head.h>
  17 #include <linux/string.h>
  18
  19 #include "adfs.h"
  20 #include "dir_fplus.h"
  21
  22 static int
  23 adfs_fplus_read(struct super_block *sb, unsigned int id, unsigned int sz, struct adfs_dir *dir)
  24 {
  25         struct adfs_bigdirheader *h;
  26         struct adfs_bigdirtail *t;
  27         unsigned long block;
  28         unsigned int blk, size;
  29         int i, ret = -EIO;
  30
  31         dir->nr_buffers = 0;
  32
  33         block = __adfs_block_map(sb, id, 0);
  34         if (!block) {
  35                 adfs_error(sb, "dir object %X has a hole at offset 0", id);
  36                 goto out;
  37         }
  38
  39         dir->bh[0] = sb_bread(sb, block);
  40         if (!dir->bh[0])
  41                 goto out;
  42         dir->nr_buffers += 1;
  43
  44         h = (struct adfs_bigdirheader *)dir->bh[0]->b_data;
  45         size = le32_to_cpu(h->bigdirsize);
  46         if (size != sz) {
  47                 printk(KERN_WARNING "adfs: adfs_fplus_read: directory header size\n"
  48                                 " does not match directory size\n");
  49         }
  50
  51         if (h->bigdirversion[0] != 0 || h->bigdirversion[1] != 0 ||
  52             h->bigdirversion[2] != 0 || size & 2047 ||
  53             h->bigdirstartname != cpu_to_le32(BIGDIRSTARTNAME))
  54                 goto out;
  55
  56         size >>= sb->s_blocksize_bits;
  57         for (blk = 1; blk < size; blk++) {
  58                 block = __adfs_block_map(sb, id, blk);
  59                 if (!block) {
  60                         adfs_error(sb, "dir object %X has a hole at offset %d", id, blk);
  61                         goto out;
  62                 }
  63
  64                 dir->bh[blk] = sb_bread(sb, block);
  65                 if (!dir->bh[blk])
  66                         goto out;
  67                 dir->nr_buffers = blk;
  68         }
  69
  70         t = (struct adfs_bigdirtail *)(dir->bh[size - 1]->b_data + (sb->s_blocksize - 8));
  71
  72         if (t->bigdirendname != cpu_to_le32(BIGDIRENDNAME) ||
  73             t->bigdirendmasseq != h->startmasseq ||
  74             t->reserved[0] != 0 || t->reserved[1] != 0)
  75                 goto out;
  76
  77         dir->parent_id = le32_to_cpu(h->bigdirparent);
  78         dir->sb = sb;
  79         return 0;
  80 out:
  81         for (i = 0; i < dir->nr_buffers; i++)
  82                 brelse(dir->bh[i]);
  83         dir->sb = NULL;
  84         return ret;
  85 }
  86
  87 static int
  88 adfs_fplus_setpos(struct adfs_dir *dir, unsigned int fpos)
  89 {
  90         struct adfs_bigdirheader *h = (struct adfs_bigdirheader *)dir->bh[0]->b_data;
  91         int ret = -ENOENT;
  92
  93         if (fpos <= le32_to_cpu(h->bigdirentries)) {
  94                 dir->pos = fpos;
  95                 ret = 0;
  96         }
  97
  98         return ret;
  99 }
 100
 101 static void
 102 dir_memcpy(struct adfs_dir *dir, unsigned int offset, void *to, int len)
 103 {
 104         struct super_block *sb = dir->sb;
 105         unsigned int buffer, partial, remainder;
 106
 107         buffer = offset >> sb->s_blocksize_bits;
 108         offset &= sb->s_blocksize - 1;
 109
 110         partial = sb->s_blocksize - offset;
 111
 112         if (partial >= len)
 113                 memcpy(to, dir->bh[buffer]->b_data + offset, len);
 114         else {
 115                 char *c = (char *)to;
 116
 117                 remainder = len - partial;
 118
 119                 memcpy(c, dir->bh[buffer]->b_data + offset, partial);
 120                 memcpy(c + partial, dir->bh[buffer + 1]->b_data, remainder);
 121         }
 122 }
 123
 124 static int
 125 adfs_fplus_getnext(struct adfs_dir *dir, struct object_info *obj)
 126 {
 127         struct adfs_bigdirheader *h = (struct adfs_bigdirheader *)dir->bh[0]->b_data;
 128         struct adfs_bigdirentry bde;
 129         unsigned int offset;
 130         int i, ret = -ENOENT;
 131
 132         if (dir->pos >= le32_to_cpu(h->bigdirentries))
 133                 goto out;
 134
 135         offset = offsetof(struct adfs_bigdirheader, bigdirname);
 136         offset += ((le32_to_cpu(h->bigdirnamelen) + 4) & ~3);
 137         offset += dir->pos * sizeof(struct adfs_bigdirentry);
 138
 139         dir_memcpy(dir, offset, &bde, sizeof(struct adfs_bigdirentry));
 140
 141         obj->loadaddr = le32_to_cpu(bde.bigdirload);
 142         obj->execaddr = le32_to_cpu(bde.bigdirexec);
 143         obj->size     = le32_to_cpu(bde.bigdirlen);
 144         obj->file_id  = le32_to_cpu(bde.bigdirindaddr);
 145         obj->attr     = le32_to_cpu(bde.bigdirattr);
 146         obj->name_len = le32_to_cpu(bde.bigdirobnamelen);
 147
 148         offset = offsetof(struct adfs_bigdirheader, bigdirname);
 149         offset += ((le32_to_cpu(h->bigdirnamelen) + 4) & ~3);
 150         offset += le32_to_cpu(h->bigdirentries) * sizeof(struct adfs_bigdirentry);
 151         offset += le32_to_cpu(bde.bigdirobnameptr);
 152
 153         dir_memcpy(dir, offset, obj->name, obj->name_len);
 154         for (i = 0; i < obj->name_len; i++)
 155                 if (obj->name[i] == '/')
 156                         obj->name[i] = '.';
 157
 158         dir->pos += 1;
 159         ret = 0;
 160 out:
 161         return ret;
 162 }
 163
 164 static void
 165 adfs_fplus_free(struct adfs_dir *dir)
 166 {
 167         int i;
 168
 169         for (i = 0; i < dir->nr_buffers; i++)
 170                 brelse(dir->bh[i]);
 171         dir->sb = NULL;
 172 }
 173
 174 struct adfs_dir_ops adfs_fplus_dir_ops = {
 175         .read           = adfs_fplus_read,
 176         .setpos         = adfs_fplus_setpos,
 177         .getnext        = adfs_fplus_getnext,
 178         .free           = adfs_fplus_free
 179 };