/*
* dosio.c -- Disk I/O module for the ext2fs/DOS library.
*
* Copyright (c) 1997 by Theodore Ts'o.
*
* Copyright (c) 1997 Mark Habersack
*
* %Begin-Header%
* This file may be redistributed under the terms of the GNU Library
* General Public License, version 2.
* %End-Header%
*/
#include <stdio.h>
#include <bios.h>
#include <string.h>
#include <ctype.h>
#include <io.h>
#ifdef HAVE_ERRNO_H
#include <errno.h>
#endif
#include <ext2fs/ext2_types.h>
#include "utils.h"
#include "dosio.h"
#include "et/com_err.h"
#include "ext2_err.h"
#include "ext2fs/io.h"
/*
* Some helper macros
*/
#define LINUX_EXT2FS 0x83
#define LINUX_SWAP 0x82
#define WRITE_ERR(_msg_) write(2, _msg_, strlen(_msg_))
#define WRITE_ERR_S(_msg_) write(2, _msg_, sizeof(_msg_))
/*
* Exported variables
*/
unsigned long _dio_error;
unsigned long _dio_hw_error;
/*
* Array of all opened partitions
*/
static PARTITION **partitions = NULL;
static unsigned short npart = 0; /* Number of mapped partitions */
static PARTITION *active = NULL;
/*
* I/O Manager routine prototypes
*/
static errcode_t dos_open(const char *dev, int flags, io_channel *channel);
static errcode_t dos_close(io_channel channel);
static errcode_t dos_set_blksize(io_channel channel, int blksize);
static errcode_t dos_read_blk(io_channel channel, unsigned long block,
int count, void *buf);
static errcode_t dos_write_blk(io_channel channel, unsigned long block,
int count, const void *buf);
static errcode_t dos_flush(io_channel channel);
static struct struct_io_manager struct_dos_manager = {
EXT2_ET_MAGIC_IO_MANAGER,
"DOS I/O Manager",
dos_open,
dos_close,
dos_set_blksize,
dos_read_blk,
dos_write_blk,
dos_flush
};
io_manager dos_io_manager = &struct_dos_manager;
/*
* Macro taken from unix_io.c
*/
/*
* For checking structure magic numbers...
*/
#define EXT2_CHECK_MAGIC(struct, code) \
if ((struct)->magic != (code)) return (code)
/*
* Calculates a CHS address of a sector from its LBA
* offset for the given partition.
*/
static void lba2chs(unsigned long lba_addr, CHS *chs, PARTITION *part)
{
unsigned long abss;
chs->offset = lba_addr & 0x000001FF;
abss = (lba_addr >> 9) + part->start;
chs->cyl = abss / (part->sects * part->heads);
chs->head = (abss / part->sects) % part->heads;
chs->sector = (abss % part->sects) + 1;
}
#ifdef __TURBOC__
#pragma argsused
#endif
/*
* Scans the passed partition table looking for *pno partition
* that has LINUX_EXT2FS type.
*
* TODO:
* For partition numbers >5 Linux uses DOS extended partitions -
* dive into them an return an appropriate entry. Also dive into
* extended partitions when scanning for a first Linux/ext2fs.
*/
static PTABLE_ENTRY *scan_partition_table(PTABLE_ENTRY *pentry,
unsigned short phys,
unsigned char *pno)
{
unsigned i;
if(*pno != 0xFF && *pno >= 5)
return NULL; /* We don't support extended partitions for now */
if(*pno != 0xFF)
{
if(pentry[*pno].type == LINUX_EXT2FS)
return &pentry[*pno];
else
{
if(!pentry[*pno].type)
*pno = 0xFE;
else if(pentry[*pno].type == LINUX_SWAP)
*pno = 0xFD;
return NULL;
}
}
for(i = 0; i < 4; i++)
if(pentry[i].type == LINUX_EXT2FS)
{
*pno = i;
return &pentry[i];
}
return NULL;
}
/*
* Allocate libext2fs structures associated with I/O manager
*/
static io_channel alloc_io_channel(PARTITION *part)
{
io_channel ioch;
ioch = (io_channel)malloc(sizeof(struct struct_io_channel));
if (!ioch)
return NULL;
memset(ioch, 0, sizeof(struct struct_io_channel));
ioch->magic = EXT2_ET_MAGIC_IO_CHANNEL;
ioch->manager = dos_io_manager;
ioch->name = (char *)malloc(strlen(part->dev)+1);
if (!ioch->name) {
free(ioch);
return NULL;
}
strcpy(ioch->name, part->dev);
ioch->private_data = part;
ioch->block_size = 1024; /* The smallest ext2fs block size */
ioch->read_error = 0;
ioch->write_error = 0;
return ioch;
}
#ifdef __TURBOC__
#pragma argsused
#endif
/*
* Open the 'name' partition, initialize all information structures
* we need to keep and create libext2fs I/O manager.
*/
static errcode_t dos_open(const char *dev, int flags, io_channel *channel)
{
unsigned char *tmp, sec[512];
PARTITION *part;
PTABLE_ENTRY *pent;
PARTITION **newparts;
if(!dev)
{
_dio_error = ERR_BADDEV;
return EXT2_ET_BAD_DEVICE_NAME;
}
/*
* First check whether the dev name is OK
*/
tmp = (unsigned char*)strrchr(dev, '/');
if(!tmp)
{
_dio_error = ERR_BADDEV;
return EXT2_ET_BAD_DEVICE_NAME;
}
*tmp = 0;
if(strcmp(dev, "/dev"))
{
_dio_error = ERR_BADDEV;
return EXT2_ET_BAD_DEVICE_NAME;
}
*tmp++ = '/';
/*
* Check whether the partition data is already in cache
*/
part = (PARTITION*)malloc(sizeof(PARTITION));
if (!part)
return ENOMEM;
{
int i = 0;
for(;i < npart; i++)
if(!strcmp(partitions[i]->dev, dev))
{
/* Found it! Make it the active one */
active = partitions[i];
*channel = alloc_io_channel(active);
if (!*channel)
return ENOMEM;
return 0;
}
}
/*
* Drive number & optionally partn number
*/
switch(tmp[0])
{
case 'h':
case 's':
part->phys = 0x80;
part->phys += toupper(tmp[2]) - 'A';
/*
* Do we have the partition number?
*/
if(tmp[3])
part->pno = isdigit((int)tmp[3]) ? tmp[3] - '0' - 1: 0;
else
part->pno = 0xFF;
break;
case 'f':
if(tmp[2])
part->phys = isdigit((int)tmp[2]) ? tmp[2] - '0' : 0;
else
part->phys = 0x00; /* We'll assume /dev/fd0 */
break;
default:
_dio_error = ERR_BADDEV;
return ENODEV;
}
if(part->phys < 0x80)
{
/* We don't support floppies for now */
_dio_error = ERR_NOTSUPP;
return EINVAL;
}
part->dev = strdup(dev);
/*
* Get drive's geometry
*/
_dio_hw_error = biosdisk(DISK_GET_GEOMETRY,
part->phys,
0, /* head */
0, /* cylinder */
1, /* sector */
1, /* just one sector */
sec);
if(!HW_OK())
{
_dio_error = ERR_HARDWARE;
free(part->dev);
free(part);
return EFAULT;
}
/*
* Calculate the geometry
*/
part->cyls = (unsigned short)(((sec[0] >> 6) << 8) + sec[1] + 1);
part->heads = sec[3] + 1;
part->sects = sec[0] & 0x3F;
/*
* Now that we know all we need, let's look for the partition
*/
_dio_hw_error = biosdisk(DISK_READ, part->phys, 0, 0, 1, 1, sec);
if(!HW_OK())
{
_dio_error = ERR_HARDWARE;
free(part->dev);
free(part);
return EFAULT;
}
pent = (PTABLE_ENTRY*)&sec[0x1BE];
pent = scan_partition_table(pent, part->phys, &part->pno);
if(!pent)
{
_dio_error = part->pno == 0xFE ? ERR_EMPTYPART :
part->pno == 0xFD ? ERR_LINUXSWAP : ERR_NOTEXT2FS;
free(part->dev);
free(part);
return ENODEV;
}
/*
* Calculate the remaining figures
*/
{
unsigned long fsec, fhead, fcyl;
fsec = (unsigned long)(pent->start_sec & 0x3F);
fhead = (unsigned long)pent->start_head;
fcyl = ((pent->start_sec >> 6) << 8) + pent->start_cyl;
part->start = fsec + fhead * part->sects + fcyl *
(part->heads * part->sects) - 1;
part->len = pent->size;
}
/*
* Add the partition to the table
*/
newparts = (PARTITION**)realloc(partitions, sizeof(PARTITION) * npart);
if (!newparts) {
free(part);
return ENOMEM;
}
partitions = newparts;
partitions[npart++] = active = part;
/*
* Now alloc all libe2fs structures
*/
*channel = alloc_io_channel(active);
if (!*channel)
return ENOMEM;
return 0;
}
static errcode_t dos_close(io_channel channel)
{
free(channel->name);
free(channel);
return 0;
}
static errcode_t dos_set_blksize(io_channel channel, int blksize)
{
channel->block_size = blksize;
return 0;
}
static errcode_t dos_read_blk(io_channel channel, unsigned long block,
int count, void *buf)
{
PARTITION *part;
size_t size;
ext2_loff_t loc;
CHS chs;
EXT2_CHECK_MAGIC(channel, EXT2_ET_MAGIC_IO_CHANNEL);
part = (PARTITION*)channel->private_data;
size = (size_t)((count < 0) ? -count : count * channel->block_size);
loc = (ext2_loff_t) block * channel->block_size;
lba2chs(loc, &chs, part);
/*
* Potential bug here:
* If DJGPP is used then reads of >18 sectors will fail!
* Have to rewrite biosdisk.
*/
_dio_hw_error = biosdisk(DISK_READ,
part->phys,
chs.head,
chs.cyl,
chs.sector,
size < 512 ? 1 : size/512,
buf);
if(!HW_OK())
{
_dio_error = ERR_HARDWARE;
return EFAULT;
}
return 0;
}
static errcode_t dos_write_blk(io_channel channel, unsigned long block,
int count, const void *buf)
{
PARTITION *part;
size_t size;
ext2_loff_t loc;
CHS chs;
EXT2_CHECK_MAGIC(channel, EXT2_ET_MAGIC_IO_CHANNEL);
part = (PARTITION*)channel->private_data;
if(count == 1)
size = (size_t)channel->block_size;
else
{
if (count < 0)
size = (size_t)-count;
else
size = (size_t)(count * channel->block_size);
}
loc = (ext2_loff_t)block * channel->block_size;
lba2chs(loc, &chs, part);
_dio_hw_error = biosdisk(DISK_WRITE,
part->phys,
chs.head,
chs.cyl,
chs.sector,
size < 512 ? 1 : size/512,
(void*)buf);
if(!HW_OK())
{
_dio_error = ERR_HARDWARE;
return EFAULT;
}
return 0;
}
#ifdef __TURBOC__
#pragma argsused
#endif
static errcode_t dos_flush(io_channel channel)
{
/*
* No buffers, no flush...
*/
return 0;
}