2 * Copyright (c) 2014 Marcel Moolenaar
5 * Redistribution and use in source and binary forms, with or without
6 * modification, are permitted provided that the following conditions
8 * 1. Redistributions of source code must retain the above copyright
9 * notice, this list of conditions and the following disclaimer.
10 * 2. Redistributions in binary form must reproduce the above copyright
11 * notice, this list of conditions and the following disclaimer in the
12 * documentation and/or other materials provided with the distribution.
14 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
15 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
16 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
17 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
18 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
19 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
20 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
21 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
22 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
23 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
27 #include <sys/cdefs.h>
28 __FBSDID("$FreeBSD$");
30 #include <sys/types.h>
31 #include <sys/endian.h>
32 #include <sys/errno.h>
43 #ifndef __has_extension
44 #define __has_extension(x) 0
49 * o File is in network byte order.
50 * o The timestamp is seconds since 1/1/2000 12:00:00 AM UTC
52 * This file is divided in 3 parts:
53 * 1. Common definitions
54 * 2. Dynamic VHD support
55 * 3. Fixed VHD support
59 * PART 1: Common definitions
62 #define VHD_SECTOR_SIZE 512
63 #define VHD_BLOCK_SIZE (4096 * VHD_SECTOR_SIZE) /* 2MB blocks */
67 #define VHD_FOOTER_COOKIE 0x636f6e6563746978
69 #define VHD_FEATURES_TEMPORARY 0x01
70 #define VHD_FEATURES_RESERVED 0x02
72 #define VHD_VERSION 0x00010000
75 uint32_t creator_tool;
76 #define VHD_CREATOR_TOOL 0x2a696d67 /* FreeBSD mkimg */
77 uint32_t creator_version;
78 #define VHD_CREATOR_VERSION 0x00010000
80 #define VHD_CREATOR_OS 0x46425344
81 uint64_t original_size;
82 uint64_t current_size;
87 #define VHD_DISK_TYPE_FIXED 2
88 #define VHD_DISK_TYPE_DYNAMIC 3
89 #define VHD_DISK_TYPE_DIFF 4
93 uint8_t _reserved[427];
95 #if __has_extension(c_static_assert)
96 _Static_assert(sizeof(struct vhd_footer) == VHD_SECTOR_SIZE,
97 "Wrong size for footer");
101 vhd_checksum(void *buf, size_t sz)
108 for (ofs = 0; ofs < sz; ofs++)
114 vhd_geometry(struct vhd_footer *footer, uint64_t image_size)
119 /* Respect command line options if possible. */
120 if (nheads > 1 && nheads < 256 &&
121 nsecs > 1 && nsecs < 256 &&
123 be16enc(&footer->cylinders, ncyls);
124 footer->heads = nheads;
125 footer->sectors = nsecs;
129 imgsz = image_size / VHD_SECTOR_SIZE;
130 if (imgsz > 65536 * 16 * 255)
131 imgsz = 65536 * 16 * 255;
132 if (imgsz >= 65535 * 16 * 63) {
133 be16enc(&footer->cylinders, imgsz / (16 * 255));
135 footer->sectors = 255;
138 footer->sectors = 17;
140 footer->heads = (cth + 1023) / 1024;
141 if (footer->heads < 4)
143 if (cth >= (footer->heads * 1024) || footer->heads > 16) {
145 footer->sectors = 31;
148 if (cth >= (footer->heads * 1024)) {
150 footer->sectors = 63;
153 be16enc(&footer->cylinders, cth / footer->heads);
163 return (t - 0x386d4380);
170 vhd_uuid_enc(void *buf, const uuid_t *uuid)
175 be32enc(p, uuid->time_low);
176 be16enc(p + 4, uuid->time_mid);
177 be16enc(p + 6, uuid->time_hi_and_version);
178 p[8] = uuid->clock_seq_hi_and_reserved;
179 p[9] = uuid->clock_seq_low;
180 for (i = 0; i < _UUID_NODE_LEN; i++)
181 p[10 + i] = uuid->node[i];
185 vhd_make_footer(struct vhd_footer *footer, uint64_t image_size,
186 uint32_t disk_type, uint64_t data_offset)
190 memset(footer, 0, sizeof(*footer));
191 be64enc(&footer->cookie, VHD_FOOTER_COOKIE);
192 be32enc(&footer->features, VHD_FEATURES_RESERVED);
193 be32enc(&footer->version, VHD_VERSION);
194 be64enc(&footer->data_offset, data_offset);
195 be32enc(&footer->timestamp, vhd_timestamp());
196 be32enc(&footer->creator_tool, VHD_CREATOR_TOOL);
197 be32enc(&footer->creator_version, VHD_CREATOR_VERSION);
198 be32enc(&footer->creator_os, VHD_CREATOR_OS);
199 be64enc(&footer->original_size, image_size);
200 be64enc(&footer->current_size, image_size);
201 vhd_geometry(footer, image_size);
202 be32enc(&footer->disk_type, disk_type);
204 vhd_uuid_enc(&footer->id, &id);
205 be32enc(&footer->checksum, vhd_checksum(footer, sizeof(*footer)));
209 * We round the image size to 2MB for both the dynamic and
210 * fixed VHD formats. For dynamic VHD, this is needed to
211 * have the image size be a multiple of the grain size. For
212 * fixed VHD this is not really needed, but makes sure that
213 * it's easy to convert from fixed VHD to dynamic VHD.
216 vhd_resize(lba_t imgsz)
220 imagesz = imgsz * secsz;
221 imagesz = (imagesz + VHD_BLOCK_SIZE - 1) & ~(VHD_BLOCK_SIZE - 1);
222 return (image_set_size(imagesz / secsz));
226 * PART 2: Dynamic VHD support
230 * copy of disk footer
231 * dynamic disk header
232 * block allocation table (BAT)
237 struct vhd_dyn_header {
239 #define VHD_HEADER_COOKIE 0x6378737061727365
240 uint64_t data_offset;
241 uint64_t table_offset;
243 uint32_t max_entries;
247 uint32_t parent_timestamp;
249 uint16_t parent_name[256]; /* UTF-16 */
253 uint32_t data_length;
255 uint64_t data_offset;
257 char _reserved2[256];
259 #if __has_extension(c_static_assert)
260 _Static_assert(sizeof(struct vhd_dyn_header) == VHD_SECTOR_SIZE * 2,
261 "Wrong size for header");
265 vhd_dyn_write(int fd)
267 struct vhd_footer footer;
268 struct vhd_dyn_header header;
270 lba_t blk, blkcnt, nblks;
275 int bat_entries, error, entry;
277 imgsz = image_get_size() * secsz;
278 bat_entries = imgsz / VHD_BLOCK_SIZE;
280 vhd_make_footer(&footer, imgsz, VHD_DISK_TYPE_DYNAMIC, sizeof(footer));
281 if (sparse_write(fd, &footer, sizeof(footer)) < 0)
284 memset(&header, 0, sizeof(header));
285 be64enc(&header.cookie, VHD_HEADER_COOKIE);
286 be64enc(&header.data_offset, ~0ULL);
287 be64enc(&header.table_offset, sizeof(footer) + sizeof(header));
288 be32enc(&header.version, VHD_VERSION);
289 be32enc(&header.max_entries, bat_entries);
290 be32enc(&header.block_size, VHD_BLOCK_SIZE);
291 be32enc(&header.checksum, vhd_checksum(&header, sizeof(header)));
292 if (sparse_write(fd, &header, sizeof(header)) < 0)
295 batsz = bat_entries * sizeof(uint32_t);
296 batsz = (batsz + VHD_SECTOR_SIZE - 1) & ~(VHD_SECTOR_SIZE - 1);
300 memset(bat, 0xff, batsz);
301 blkcnt = VHD_BLOCK_SIZE / secsz;
302 sector = (sizeof(footer) + sizeof(header) + batsz) / VHD_SECTOR_SIZE;
303 for (entry = 0; entry < bat_entries; entry++) {
304 blk = entry * blkcnt;
305 if (image_data(blk, blkcnt)) {
306 be32enc(&bat[entry], sector);
307 sector += (VHD_BLOCK_SIZE / VHD_SECTOR_SIZE) + 1;
310 if (sparse_write(fd, bat, batsz) < 0) {
316 bitmap = malloc(VHD_SECTOR_SIZE);
319 memset(bitmap, 0xff, VHD_SECTOR_SIZE);
322 blkcnt = VHD_BLOCK_SIZE / secsz;
323 nblks = image_get_size();
324 while (blk < nblks) {
325 if (!image_data(blk, blkcnt)) {
329 if (sparse_write(fd, bitmap, VHD_SECTOR_SIZE) < 0) {
333 error = image_copyout_region(fd, blk, blkcnt);
342 if (sparse_write(fd, &footer, sizeof(footer)) < 0)
348 static struct mkimg_format vhd_dyn_format = {
350 .description = "Virtual Hard Disk",
351 .resize = vhd_resize,
352 .write = vhd_dyn_write,
355 FORMAT_DEFINE(vhd_dyn_format);
362 vhd_fix_write(int fd)
364 struct vhd_footer footer;
368 error = image_copyout(fd);
370 imgsz = image_get_size() * secsz;
371 vhd_make_footer(&footer, imgsz, VHD_DISK_TYPE_FIXED, ~0ULL);
372 if (sparse_write(fd, &footer, sizeof(footer)) < 0)
378 static struct mkimg_format vhd_fix_format = {
380 .description = "Fixed Virtual Hard Disk",
381 .resize = vhd_resize,
382 .write = vhd_fix_write,
385 FORMAT_DEFINE(vhd_fix_format);