fs/ext2/dev.c

   1 /*
   2  * (C) Copyright 2004
   3  *  esd gmbh <www.esd-electronics.com>
   4  *  Reinhard Arlt <reinhard.arlt@esd-electronics.com>
   5  *
   6  *  based on code of fs/reiserfs/dev.c by
   7  *
   8  *  (C) Copyright 2003 - 2004
   9  *  Sysgo AG, <www.elinos.com>, Pavel Bartusek <pba@sysgo.com>
  10  *
  11  *  This program is free software; you can redistribute it and/or modify
  12  *  it under the terms of the GNU General Public License as published by
  13  *  the Free Software Foundation; either version 2 of the License, or
  14  *  (at your option) any later version.
  15  *
  16  *  This program is distributed in the hope that it will be useful,
  17  *  but WITHOUT ANY WARRANTY; without even the implied warranty of
  18  *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  19  *  GNU General Public License for more details.
  20  *
  21  *  You should have received a copy of the GNU General Public License
  22  *  along with this program; if not, write to the Free Software
  23  *  Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
  24  */
  25
  26
  27 #include <common.h>
  28 #include <config.h>
  29 #include <ext2fs.h>
  30
  31 static block_dev_desc_t *ext2fs_block_dev_desc;
  32 static disk_partition_t part_info;
  33
  34 int ext2fs_set_blk_dev (block_dev_desc_t * rbdd, int part)
  35 {
  36         ext2fs_block_dev_desc = rbdd;
  37
  38         if (part == 0) {
  39                 /* disk doesn't use partition table */
  40                 part_info.start = 0;
  41                 part_info.size = rbdd->lba;
  42                 part_info.blksz = rbdd->blksz;
  43         } else {
  44                 if (get_partition_info
  45                     (ext2fs_block_dev_desc, part, &part_info)) {
  46                         return 0;
  47                 }
  48         }
  49         return (part_info.size);
  50 }
  51
  52
  53 int ext2fs_devread (int sector, int byte_offset, int byte_len, char *buf) {
  54         char sec_buf[SECTOR_SIZE];
  55         unsigned block_len;
  56
  57 /*
  58  *  Check partition boundaries
  59  */
  60         if ((sector < 0)
  61             || ((sector + ((byte_offset + byte_len - 1) >> SECTOR_BITS)) >=
  62                 part_info.size)) {
  63         /*      errnum = ERR_OUTSIDE_PART; */
  64                 printf (" ** ext2fs_devread() read outside partition sector %d\n", sector);
  65                 return (0);
  66         }
  67
  68 /*
  69  *  Get the read to the beginning of a partition.
  70  */
  71         sector += byte_offset >> SECTOR_BITS;
  72         byte_offset &= SECTOR_SIZE - 1;
  73
  74         debug (" <%d, %d, %d>\n", sector, byte_offset, byte_len);
  75
  76         if (ext2fs_block_dev_desc == NULL) {
  77                 printf ("** Invalid Block Device Descriptor (NULL)\n");
  78                 return (0);
  79         }
  80
  81         if (byte_offset != 0) {
  82                 /* read first part which isn't aligned with start of sector */
  83                 if (ext2fs_block_dev_desc->
  84                     block_read (ext2fs_block_dev_desc->dev,
  85                                 part_info.start + sector, 1,
  86                                 (unsigned long *) sec_buf) != 1) {
  87                         printf (" ** ext2fs_devread() read error **\n");
  88                         return (0);
  89                 }
  90                 memcpy (buf, sec_buf + byte_offset,
  91                         min (SECTOR_SIZE - byte_offset, byte_len));
  92                 buf += min (SECTOR_SIZE - byte_offset, byte_len);
  93                 byte_len -= min (SECTOR_SIZE - byte_offset, byte_len);
  94                 sector++;
  95         }
  96
  97         if (byte_len == 0)
  98                 return 1;
  99
 100         /*  read sector aligned part */
 101         block_len = byte_len & ~(SECTOR_SIZE - 1);
 102
 103         if (block_len == 0) {
 104                 u8 p[SECTOR_SIZE];
 105
 106                 block_len = SECTOR_SIZE;
 107                 ext2fs_block_dev_desc->block_read(ext2fs_block_dev_desc->dev,
 108                                                   part_info.start + sector,
 109                                                   1, (unsigned long *)p);
 110                 memcpy(buf, p, byte_len);
 111                 return 1;
 112         }
 113
 114         if (ext2fs_block_dev_desc->block_read (ext2fs_block_dev_desc->dev,
 115                                                part_info.start + sector,
 116                                                block_len / SECTOR_SIZE,
 117                                                (unsigned long *) buf) !=
 118             block_len / SECTOR_SIZE) {
 119                 printf (" ** ext2fs_devread() read error - block\n");
 120                 return (0);
 121         }
 122         block_len = byte_len & ~(SECTOR_SIZE - 1);
 123         buf += block_len;
 124         byte_len -= block_len;
 125         sector += block_len / SECTOR_SIZE;
 126
 127         if (byte_len != 0) {
 128                 /* read rest of data which are not in whole sector */
 129                 if (ext2fs_block_dev_desc->
 130                     block_read (ext2fs_block_dev_desc->dev,
 131                                 part_info.start + sector, 1,
 132                                 (unsigned long *) sec_buf) != 1) {
 133                         printf (" ** ext2fs_devread() read error - last part\n");
 134                         return (0);
 135                 }
 136                 memcpy (buf, sec_buf, byte_len);
 137         }
 138         return (1);
 139 }