Bochs/bochs/iodev/hdimage/vpc-img.cc

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/////////////////////////////////////////////////////////////////////////
// $Id$
/////////////////////////////////////////////////////////////////////////
//
// Block driver for Connectix / Microsoft Virtual PC images (ported from QEMU)
//
// Copyright (c) 2005 Alex Beregszaszi
// Copyright (c) 2009 Kevin Wolf <kwolf@suse.de>
// Copyright (C) 2012 The Bochs Project
//
// Permission is hereby granted, free of charge, to any person obtaining a copy
// of this software and associated documentation files (the "Software"), to deal
// in the Software without restriction, including without limitation the rights
// to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
// copies of the Software, and to permit persons to whom the Software is
// furnished to do so, subject to the following conditions:
//
// The above copyright notice and this permission notice shall be included in
// all copies or substantial portions of the Software.
//
// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
// THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
// OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
// THE SOFTWARE.
//
/////////////////////////////////////////////////////////////////////////
// Define BX_PLUGGABLE in files that can be compiled into plugins. For
// platforms that require a special tag on exported symbols, BX_PLUGGABLE
// is used to know when we are exporting symbols and when we are importing.
#define BX_PLUGGABLE
#include "iodev.h"
#include "hdimage.h"
#include "vpc-img.h"
#define LOG_THIS bx_devices.pluginHDImageCtl->
// be*_to_cpu : convert disk (big) to host endianness
#if defined (BX_LITTLE_ENDIAN)
#define be16_to_cpu(val) bx_bswap16(val)
#define be32_to_cpu(val) bx_bswap32(val)
#define be64_to_cpu(val) bx_bswap64(val)
#define cpu_to_be32(val) bx_bswap32(val)
#else
#define be16_to_cpu(val) (val)
#define be32_to_cpu(val) (val)
#define be64_to_cpu(val) (val)
#define cpu_to_be32(val) (val)
#endif
int vpc_image_t::check_format(int fd, Bit64u imgsize)
{
Bit8u temp_footer_buf[HEADER_SIZE];
vhd_footer_t *footer;
int vpc_disk_type = VHD_DYNAMIC;
if (bx_read_image(fd, 0, (char*)temp_footer_buf, HEADER_SIZE) != HEADER_SIZE) {
return HDIMAGE_READ_ERROR;
}
footer = (vhd_footer_t*)temp_footer_buf;
if (strncmp((char*)footer->creator, "conectix", 8)) {
if (imgsize < HEADER_SIZE) {
return HDIMAGE_NO_SIGNATURE;
}
// If a fixed disk, the footer is found only at the end of the file
if (bx_read_image(fd, imgsize-HEADER_SIZE, (char*)temp_footer_buf, HEADER_SIZE) != HEADER_SIZE) {
return HDIMAGE_READ_ERROR;
}
if (strncmp((char*)footer->creator, "conectix", 8)) {
return HDIMAGE_NO_SIGNATURE;
}
vpc_disk_type = VHD_FIXED;
}
return vpc_disk_type;
}
int vpc_image_t::open(const char* _pathname)
{
int i;
vhd_footer_t *footer;
vhd_dyndisk_header_t *dyndisk_header;
Bit8u buf[HEADER_SIZE];
Bit32u checksum;
Bit64u imgsize = 0;
int disk_type;
pathname = _pathname;
if ((fd = hdimage_open_file(pathname, O_RDWR, &imgsize, NULL)) < 0) {
BX_ERROR(("VPC: cannot open hdimage file '%s'", pathname));
return -1;
}
disk_type = check_format(fd, imgsize);
if (disk_type < 0) {
switch (disk_type) {
case HDIMAGE_READ_ERROR:
BX_ERROR(("VPC: cannot read image file header of '%s'", _pathname));
return -1;
case HDIMAGE_NO_SIGNATURE:
BX_ERROR(("VPC: signature missed in file '%s'", _pathname));
return -1;
}
}
if (bx_read_image(fd, 0, (char*)footer_buf, HEADER_SIZE) != HEADER_SIZE) {
return -1;
}
footer = (vhd_footer_t*)footer_buf;
checksum = be32_to_cpu(footer->checksum);
footer->checksum = 0;
if (vpc_checksum(footer_buf, HEADER_SIZE) != checksum)
BX_ERROR(("The header checksum of '%s' is incorrect", pathname));
// Write 'checksum' back to footer, or else will leave it with zero.
footer->checksum = be32_to_cpu(checksum);
// The visible size of a image in Virtual PC depends on the geometry
// rather than on the size stored in the footer (the size in the footer
// is too large usually)
cylinders = be16_to_cpu(footer->cyls);
heads = footer->heads;
spt = footer->secs_per_cyl;
sector_count = (Bit64u)(cylinders * heads * spt);
hd_size = sector_count * 512;
if (sector_count >= 65535 * 16 * 255) {
::close(fd);
return -EFBIG;
}
if (disk_type == VHD_DYNAMIC) {
if (bx_read_image(fd, be64_to_cpu(footer->data_offset), buf, HEADER_SIZE) != HEADER_SIZE) {
::close(fd);
return -1;
}
dyndisk_header = (vhd_dyndisk_header_t*)buf;
if (strncmp((char*)dyndisk_header->magic, "cxsparse", 8)) {
::close(fd);
return -1;
}
block_size = be32_to_cpu(dyndisk_header->block_size);
bitmap_size = ((block_size / (8 * 512)) + 511) & ~511;
max_table_entries = be32_to_cpu(dyndisk_header->max_table_entries);
pagetable = new Bit32u[max_table_entries];
bat_offset = be64_to_cpu(dyndisk_header->table_offset);
if (bx_read_image(fd, bat_offset, (void*)pagetable, max_table_entries * 4) != (max_table_entries * 4)) {
::close(fd);
return -1;
}
free_data_block_offset = (bat_offset + (max_table_entries * 4) + 511) & ~511;
for (i = 0; i < max_table_entries; i++) {
pagetable[i] = be32_to_cpu(pagetable[i]);
if (pagetable[i] != 0xFFFFFFFF) {
Bit64s next = (512 * (Bit64s)pagetable[i]) + bitmap_size + block_size;
if (next > (Bit64s)free_data_block_offset) {
free_data_block_offset = next;
}
}
}
last_bitmap_offset = (Bit64s) -1;
}
cur_sector = 0;
BX_INFO(("'vpc' disk image opened: path is '%s'", pathname));
return 0;
}
void vpc_image_t::close(void)
{
if (fd > -1) {
delete [] pagetable;
::close(fd);
}
}
Bit64s vpc_image_t::lseek(Bit64s offset, int whence)
{
if (whence == SEEK_SET) {
cur_sector = (Bit32u)(offset / 512);
} else if (whence == SEEK_CUR) {
cur_sector += (Bit32u)(offset / 512);
} else {
BX_ERROR(("lseek: mode not supported yet"));
return -1;
}
if (cur_sector >= sector_count)
return -1;
return 0;
}
ssize_t vpc_image_t::read(void* buf, size_t count)
{
char *cbuf = (char*)buf;
Bit32u scount = (Bit32u)(count / 0x200);
vhd_footer_t *footer = (vhd_footer_t*)footer_buf;
Bit64s offset, sectors, sectors_per_block;
int ret;
if (cpu_to_be32(footer->type) == VHD_FIXED) {
return bx_read_image(fd, cur_sector * 512, buf, count);
}
while (scount > 0) {
offset = get_sector_offset(cur_sector, 0);
sectors_per_block = block_size >> 9;
sectors = sectors_per_block - (cur_sector % sectors_per_block);
if (sectors > scount) {
sectors = scount;
}
if (offset == -1) {
memset(buf, 0, 512);
} else {
ret = bx_read_image(fd, offset, cbuf, sectors * 512);
if (ret != 512) {
return -1;
}
}
scount -= sectors;
cur_sector += sectors;
cbuf += sectors * 512;
}
return count;
}
ssize_t vpc_image_t::write(const void* buf, size_t count)
{
char *cbuf = (char*)buf;
Bit32u scount = (Bit32u)(count / 512);
vhd_footer_t *footer = (vhd_footer_t*)footer_buf;
Bit64s offset, sectors, sectors_per_block;
int ret;
if (cpu_to_be32(footer->type) == VHD_FIXED) {
return bx_write_image(fd, cur_sector * 512, (void*)buf, count);
}
while (scount > 0) {
offset = get_sector_offset(cur_sector, 1);
sectors_per_block = block_size >> 9;
sectors = sectors_per_block - (cur_sector % sectors_per_block);
if (sectors > scount) {
sectors = scount;
}
if (offset == -1) {
offset = alloc_block(cur_sector);
if (offset < 0)
return -1;
}
ret = bx_write_image(fd, offset, cbuf, sectors * 512);
if (ret != sectors * 512) {
return -1;
}
scount -= sectors;
cur_sector += sectors;
cbuf += sectors * 512;
}
return count;
}
Bit32u vpc_image_t::get_capabilities(void)
{
return HDIMAGE_HAS_GEOMETRY;
}
bx_bool vpc_image_t::save_state(const char *backup_fname)
{
return hdimage_backup_file(fd, backup_fname);
}
void vpc_image_t::restore_state(const char *backup_fname)
{
int temp_fd;
Bit64u imgsize;
if ((temp_fd = hdimage_open_file(backup_fname, O_RDONLY, &imgsize, NULL)) < 0) {
BX_PANIC(("cannot open vpc image backup '%s'", backup_fname));
return;
}
if (check_format(temp_fd, imgsize) < HDIMAGE_FORMAT_OK) {
::close(temp_fd);
BX_PANIC(("Could not detect vpc image header"));
return;
}
::close(temp_fd);
close();
if (!hdimage_copy_file(backup_fname, pathname)) {
BX_PANIC(("Failed to restore vpc image '%s'", pathname));
return;
}
open(pathname);
}
Bit32u vpc_image_t::vpc_checksum(Bit8u *buf, size_t size)
{
Bit32u res = 0;
unsigned i;
for (i = 0; i < size; i++)
res += buf[i];
return ~res;
}
/*
* Returns the absolute byte offset of the given sector in the image file.
* If the sector is not allocated, -1 is returned instead.
*
* The parameter write must be 1 if the offset will be used for a write
* operation (the block bitmaps is updated then), 0 otherwise.
*/
Bit64s vpc_image_t::get_sector_offset(Bit64s sector_num, int write)
{
Bit64u offset = sector_num * 512;
Bit64u bitmap_offset, block_offset;
Bit32u pagetable_index, pageentry_index;
pagetable_index = offset / block_size;
pageentry_index = (offset % block_size) / 512;
if ((pagetable_index >= (Bit32u)max_table_entries) ||
(pagetable[pagetable_index] == 0xffffffff))
return -1; // not allocated
bitmap_offset = 512 * (Bit64u) pagetable[pagetable_index];
block_offset = bitmap_offset + bitmap_size + (512 * pageentry_index);
// We must ensure that we don't write to any sectors which are marked as
// unused in the bitmap. We get away with setting all bits in the block
// bitmap each time we write to a new block. This might cause Virtual PC to
// miss sparse read optimization, but it's not a problem in terms of
// correctness.
if (write && (last_bitmap_offset != bitmap_offset)) {
Bit8u *bitmap = new Bit8u[bitmap_size];
last_bitmap_offset = bitmap_offset;
memset(bitmap, 0xff, bitmap_size);
bx_write_image(fd, bitmap_offset, bitmap, bitmap_size);
delete [] bitmap;
}
return (Bit64s)block_offset;
}
/*
* Writes the footer to the end of the image file. This is needed when the
* file grows as it overwrites the old footer
*
* Returns 0 on success and < 0 on error
*/
int vpc_image_t::rewrite_footer()
{
int ret;
Bit64s offset = free_data_block_offset;
ret = bx_write_image(fd, offset, footer_buf, HEADER_SIZE);
if (ret < 0)
return ret;
return 0;
}
/*
* Allocates a new block. This involves writing a new footer and updating
* the Block Allocation Table to use the space at the old end of the image
* file (overwriting the old footer)
*
* Returns the sectors' offset in the image file on success and < 0 on error
*/
Bit64s vpc_image_t::alloc_block(Bit64s sector_num)
{
Bit64s new_bat_offset;
Bit64u old_fdbo;
Bit32u index, bat_value;
int ret;
// Check if sector_num is valid
if ((sector_num < 0) || (sector_num > sector_count))
return -1;
// Write entry into in-memory BAT
index = (sector_num * 512) / block_size;
if (pagetable[index] != 0xFFFFFFFF)
return -1;
pagetable[index] = free_data_block_offset / 512;
// Initialize the block's bitmap
Bit8u *bitmap = new Bit8u[bitmap_size];
memset(bitmap, 0xff, bitmap_size);
ret = bx_write_image(fd, free_data_block_offset, bitmap, bitmap_size);
delete [] bitmap;
if (ret < 0) {
return ret;
}
// Write new footer (the old one will be overwritten)
old_fdbo = free_data_block_offset;
free_data_block_offset += (block_size + bitmap_size);
ret = rewrite_footer();
if (ret < 0) {
free_data_block_offset = old_fdbo;
return -1;
}
// Write BAT entry to disk
new_bat_offset = bat_offset + (4 * index);
bat_value = be32_to_cpu(pagetable[index]);
ret = bx_write_image(fd, new_bat_offset, &bat_value, 4);
if (ret < 0) {
free_data_block_offset = old_fdbo;
return -1;
}
return get_sector_offset(sector_num, 0);
}