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freebsd/usr.bin/mkimg/vhd.c
Marcel Moolenaar c20f01c4ea Fix the dynamic VHD format to work with qemu. The size of the disk
is taken to match the geometry and only when the geometry is max'd
out, is the actual recorded size taken.

Note that qemu has the same logic for the fixed VHD format. However
that is known to conflict with Microsoft Azure, where the recorded
size of the image is what counts.

Pointed out by: gjb@
2015-08-07 04:27:51 +00:00

433 lines
10 KiB
C

/*-
* Copyright (c) 2014, 2015 Marcel Moolenaar
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*/
#include <sys/cdefs.h>
__FBSDID("$FreeBSD$");
#include <sys/types.h>
#include <sys/endian.h>
#include <sys/errno.h>
#include <stdlib.h>
#include <string.h>
#include <time.h>
#include <unistd.h>
#include <uuid.h>
#include "image.h"
#include "format.h"
#include "mkimg.h"
#ifndef __has_extension
#define __has_extension(x) 0
#endif
/*
* General notes:
* o File is in network byte order.
* o The timestamp is seconds since 1/1/2000 12:00:00 AM UTC
*
* This file is divided in 3 parts:
* 1. Common definitions
* 2. Dynamic VHD support
* 3. Fixed VHD support
*/
/*
* PART 1: Common definitions
*/
#define VHD_SECTOR_SIZE 512
#define VHD_BLOCK_SIZE (4096 * VHD_SECTOR_SIZE) /* 2MB blocks */
struct vhd_geom {
uint16_t cylinders;
uint8_t heads;
uint8_t sectors;
};
struct vhd_footer {
uint64_t cookie;
#define VHD_FOOTER_COOKIE 0x636f6e6563746978ULL
uint32_t features;
#define VHD_FEATURES_TEMPORARY 0x01
#define VHD_FEATURES_RESERVED 0x02
uint32_t version;
#define VHD_VERSION 0x00010000
uint64_t data_offset;
uint32_t timestamp;
uint32_t creator_tool;
#define VHD_CREATOR_TOOL 0x2a696d67 /* FreeBSD mkimg */
uint32_t creator_version;
#define VHD_CREATOR_VERSION 0x00020000
uint32_t creator_os;
#define VHD_CREATOR_OS 0x5769326b /* Wi2k */
uint64_t original_size;
uint64_t current_size;
struct vhd_geom geometry;
uint32_t disk_type;
#define VHD_DISK_TYPE_FIXED 2
#define VHD_DISK_TYPE_DYNAMIC 3
#define VHD_DISK_TYPE_DIFF 4
uint32_t checksum;
uuid_t id;
uint8_t saved_state;
uint8_t _reserved[427];
};
#if __has_extension(c_static_assert)
_Static_assert(sizeof(struct vhd_footer) == VHD_SECTOR_SIZE,
"Wrong size for footer");
#endif
static uint32_t
vhd_checksum(void *buf, size_t sz)
{
uint8_t *p = buf;
uint32_t sum;
size_t ofs;
sum = 0;
for (ofs = 0; ofs < sz; ofs++)
sum += p[ofs];
return (~sum);
}
static void
vhd_geometry(uint64_t image_size, struct vhd_geom *geom)
{
lba_t imgsz;
long cth;
imgsz = image_size / VHD_SECTOR_SIZE;
/* Respect command line options if possible. */
if (nheads > 1 && nheads < 256 &&
nsecs > 1 && nsecs < 256 &&
ncyls < 65536) {
geom->cylinders = (ncyls != 0) ? ncyls :
imgsz / (nheads * nsecs);
geom->heads = nheads;
geom->sectors = nsecs;
return;
}
if (imgsz > 65536 * 16 * 255)
imgsz = 65536 * 16 * 255;
if (imgsz >= 65535 * 16 * 63) {
geom->cylinders = imgsz / (16 * 255);
geom->heads = 16;
geom->sectors = 255;
return;
}
geom->sectors = 17;
cth = imgsz / 17;
geom->heads = (cth + 1023) / 1024;
if (geom->heads < 4)
geom->heads = 4;
if (cth >= (geom->heads * 1024) || geom->heads > 16) {
geom->heads = 16;
geom->sectors = 31;
cth = imgsz / 31;
}
if (cth >= (geom->heads * 1024)) {
geom->heads = 16;
geom->sectors = 63;
cth = imgsz / 63;
}
geom->cylinders = cth / geom->heads;
}
static uint64_t
vhd_resize(uint64_t origsz)
{
struct vhd_geom geom;
uint64_t newsz;
/*
* Round the image size to the pre-determined geometry that
* matches the image size. This circular dependency implies
* that we need to loop to handle boundary conditions.
* The first time, newsz equals origsz and the geometry will
* typically yield a new size that's smaller. We keep adding
* cylinder's worth of sectors to the new size until its
* larger or equal or origsz. But during those iterations,
* the geometry can change, so we need to account for that.
*/
newsz = origsz;
while (1) {
vhd_geometry(newsz, &geom);
newsz = (int64_t)geom.cylinders * geom.heads *
geom.sectors * VHD_SECTOR_SIZE;
if (newsz >= origsz)
break;
newsz += geom.heads * geom.sectors * VHD_SECTOR_SIZE;
}
return (newsz);
}
static uint32_t
vhd_timestamp(void)
{
time_t t;
if (!unit_testing) {
t = time(NULL);
return (t - 0x386d4380);
}
return (0x01234567);
}
static void
vhd_uuid_enc(void *buf, const uuid_t *uuid)
{
uint8_t *p = buf;
int i;
be32enc(p, uuid->time_low);
be16enc(p + 4, uuid->time_mid);
be16enc(p + 6, uuid->time_hi_and_version);
p[8] = uuid->clock_seq_hi_and_reserved;
p[9] = uuid->clock_seq_low;
for (i = 0; i < _UUID_NODE_LEN; i++)
p[10 + i] = uuid->node[i];
}
static void
vhd_make_footer(struct vhd_footer *footer, uint64_t image_size,
uint32_t disk_type, uint64_t data_offset)
{
uuid_t id;
memset(footer, 0, sizeof(*footer));
be64enc(&footer->cookie, VHD_FOOTER_COOKIE);
be32enc(&footer->features, VHD_FEATURES_RESERVED);
be32enc(&footer->version, VHD_VERSION);
be64enc(&footer->data_offset, data_offset);
be32enc(&footer->timestamp, vhd_timestamp());
be32enc(&footer->creator_tool, VHD_CREATOR_TOOL);
be32enc(&footer->creator_version, VHD_CREATOR_VERSION);
be32enc(&footer->creator_os, VHD_CREATOR_OS);
be64enc(&footer->original_size, image_size);
be64enc(&footer->current_size, image_size);
vhd_geometry(image_size, &footer->geometry);
be16enc(&footer->geometry.cylinders, footer->geometry.cylinders);
be32enc(&footer->disk_type, disk_type);
mkimg_uuid(&id);
vhd_uuid_enc(&footer->id, &id);
be32enc(&footer->checksum, vhd_checksum(footer, sizeof(*footer)));
}
/*
* PART 2: Dynamic VHD support
*
* Notes:
* o File layout:
* copy of disk footer
* dynamic disk header
* block allocation table (BAT)
* data blocks
* disk footer
*/
struct vhd_dyn_header {
uint64_t cookie;
#define VHD_HEADER_COOKIE 0x6378737061727365ULL
uint64_t data_offset;
uint64_t table_offset;
uint32_t version;
uint32_t max_entries;
uint32_t block_size;
uint32_t checksum;
uuid_t parent_id;
uint32_t parent_timestamp;
char _reserved1[4];
uint16_t parent_name[256]; /* UTF-16 */
struct {
uint32_t code;
uint32_t data_space;
uint32_t data_length;
uint32_t _reserved;
uint64_t data_offset;
} parent_locator[8];
char _reserved2[256];
};
#if __has_extension(c_static_assert)
_Static_assert(sizeof(struct vhd_dyn_header) == VHD_SECTOR_SIZE * 2,
"Wrong size for header");
#endif
static int
vhd_dyn_resize(lba_t imgsz)
{
uint64_t imagesz;
imagesz = vhd_resize(imgsz * secsz);
return (image_set_size(imagesz / secsz));
}
static int
vhd_dyn_write(int fd)
{
struct vhd_footer footer;
struct vhd_dyn_header header;
uint64_t imgsz, rawsz;
lba_t blk, blkcnt, nblks;
uint32_t *bat;
void *bitmap;
size_t batsz;
uint32_t sector;
int bat_entries, error, entry;
rawsz = image_get_size() * secsz;
imgsz = (rawsz + VHD_BLOCK_SIZE - 1) & ~(VHD_BLOCK_SIZE - 1);
vhd_make_footer(&footer, rawsz, VHD_DISK_TYPE_DYNAMIC, sizeof(footer));
if (sparse_write(fd, &footer, sizeof(footer)) < 0)
return (errno);
bat_entries = imgsz / VHD_BLOCK_SIZE;
memset(&header, 0, sizeof(header));
be64enc(&header.cookie, VHD_HEADER_COOKIE);
be64enc(&header.data_offset, ~0ULL);
be64enc(&header.table_offset, sizeof(footer) + sizeof(header));
be32enc(&header.version, VHD_VERSION);
be32enc(&header.max_entries, bat_entries);
be32enc(&header.block_size, VHD_BLOCK_SIZE);
be32enc(&header.checksum, vhd_checksum(&header, sizeof(header)));
if (sparse_write(fd, &header, sizeof(header)) < 0)
return (errno);
batsz = bat_entries * sizeof(uint32_t);
batsz = (batsz + VHD_SECTOR_SIZE - 1) & ~(VHD_SECTOR_SIZE - 1);
bat = malloc(batsz);
if (bat == NULL)
return (errno);
memset(bat, 0xff, batsz);
blkcnt = VHD_BLOCK_SIZE / secsz;
sector = (sizeof(footer) + sizeof(header) + batsz) / VHD_SECTOR_SIZE;
for (entry = 0; entry < bat_entries; entry++) {
blk = entry * blkcnt;
if (image_data(blk, blkcnt)) {
be32enc(&bat[entry], sector);
sector += (VHD_BLOCK_SIZE / VHD_SECTOR_SIZE) + 1;
}
}
if (sparse_write(fd, bat, batsz) < 0) {
free(bat);
return (errno);
}
free(bat);
bitmap = malloc(VHD_SECTOR_SIZE);
if (bitmap == NULL)
return (errno);
memset(bitmap, 0xff, VHD_SECTOR_SIZE);
blk = 0;
blkcnt = VHD_BLOCK_SIZE / secsz;
error = 0;
nblks = rawsz / secsz;
while (blk < nblks) {
if (!image_data(blk, blkcnt)) {
blk += blkcnt;
continue;
}
if (sparse_write(fd, bitmap, VHD_SECTOR_SIZE) < 0) {
error = errno;
break;
}
/* Handle partial last block */
if (blk + blkcnt > nblks)
blkcnt = nblks - blk;
error = image_copyout_region(fd, blk, blkcnt);
if (error)
break;
blk += blkcnt;
}
free(bitmap);
if (error)
return (error);
error = image_copyout_zeroes(fd, imgsz - rawsz);
if (error)
return (error);
if (sparse_write(fd, &footer, sizeof(footer)) < 0)
return (errno);
return (0);
}
static struct mkimg_format vhd_dyn_format = {
.name = "vhd",
.description = "Virtual Hard Disk",
.resize = vhd_dyn_resize,
.write = vhd_dyn_write,
};
FORMAT_DEFINE(vhd_dyn_format);
/*
* PART 3: Fixed VHD
*/
static int
vhd_fix_resize(lba_t imgsz)
{
uint64_t imagesz;
imagesz = vhd_resize(imgsz * secsz);
/*
* Azure demands that images are a whole number of megabytes.
*/
imagesz = (imagesz + 0xfffffULL) & ~0xfffffULL;
return (image_set_size(imagesz / secsz));
}
static int
vhd_fix_write(int fd)
{
struct vhd_footer footer;
uint64_t imagesz;
int error;
error = image_copyout(fd);
if (error)
return (error);
imagesz = image_get_size() * secsz;
vhd_make_footer(&footer, imagesz, VHD_DISK_TYPE_FIXED, ~0ULL);
error = (sparse_write(fd, &footer, sizeof(footer)) < 0) ? errno : 0;
return (error);
}
static struct mkimg_format vhd_fix_format = {
.name = "vhdf",
.description = "Fixed Virtual Hard Disk",
.resize = vhd_fix_resize,
.write = vhd_fix_write,
};
FORMAT_DEFINE(vhd_fix_format);