Annotation of qemu/block/vpc.c, revision 1.1.1.5

1.1       root        1: /*
1.1.1.2   root        2:  * Block driver for Connectix / Microsoft Virtual PC images
1.1       root        3:  *
                      4:  * Copyright (c) 2005 Alex Beregszaszi
                      5:  * Copyright (c) 2009 Kevin Wolf <[email protected]>
                      6:  *
                      7:  * Permission is hereby granted, free of charge, to any person obtaining a copy
                      8:  * of this software and associated documentation files (the "Software"), to deal
                      9:  * in the Software without restriction, including without limitation the rights
                     10:  * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
                     11:  * copies of the Software, and to permit persons to whom the Software is
                     12:  * furnished to do so, subject to the following conditions:
                     13:  *
                     14:  * The above copyright notice and this permission notice shall be included in
                     15:  * all copies or substantial portions of the Software.
                     16:  *
                     17:  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
                     18:  * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
                     19:  * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
                     20:  * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
                     21:  * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
                     22:  * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
                     23:  * THE SOFTWARE.
                     24:  */
                     25: #include "qemu-common.h"
                     26: #include "block_int.h"
                     27: #include "module.h"
                     28: 
                     29: /**************************************************************/
                     30: 
                     31: #define HEADER_SIZE 512
                     32: 
                     33: //#define CACHE
                     34: 
                     35: enum vhd_type {
                     36:     VHD_FIXED           = 2,
                     37:     VHD_DYNAMIC         = 3,
                     38:     VHD_DIFFERENCING    = 4,
                     39: };
                     40: 
                     41: // Seconds since Jan 1, 2000 0:00:00 (UTC)
                     42: #define VHD_TIMESTAMP_BASE 946684800
                     43: 
                     44: // always big-endian
                     45: struct vhd_footer {
                     46:     char        creator[8]; // "conectix"
                     47:     uint32_t    features;
                     48:     uint32_t    version;
                     49: 
                     50:     // Offset of next header structure, 0xFFFFFFFF if none
                     51:     uint64_t    data_offset;
                     52: 
                     53:     // Seconds since Jan 1, 2000 0:00:00 (UTC)
                     54:     uint32_t    timestamp;
                     55: 
                     56:     char        creator_app[4]; // "vpc "
                     57:     uint16_t    major;
                     58:     uint16_t    minor;
                     59:     char        creator_os[4]; // "Wi2k"
                     60: 
                     61:     uint64_t    orig_size;
                     62:     uint64_t    size;
                     63: 
                     64:     uint16_t    cyls;
                     65:     uint8_t     heads;
                     66:     uint8_t     secs_per_cyl;
                     67: 
                     68:     uint32_t    type;
                     69: 
                     70:     // Checksum of the Hard Disk Footer ("one's complement of the sum of all
                     71:     // the bytes in the footer without the checksum field")
                     72:     uint32_t    checksum;
                     73: 
                     74:     // UUID used to identify a parent hard disk (backing file)
                     75:     uint8_t     uuid[16];
                     76: 
                     77:     uint8_t     in_saved_state;
                     78: };
                     79: 
                     80: struct vhd_dyndisk_header {
                     81:     char        magic[8]; // "cxsparse"
                     82: 
                     83:     // Offset of next header structure, 0xFFFFFFFF if none
                     84:     uint64_t    data_offset;
                     85: 
                     86:     // Offset of the Block Allocation Table (BAT)
                     87:     uint64_t    table_offset;
                     88: 
                     89:     uint32_t    version;
                     90:     uint32_t    max_table_entries; // 32bit/entry
                     91: 
                     92:     // 2 MB by default, must be a power of two
                     93:     uint32_t    block_size;
                     94: 
                     95:     uint32_t    checksum;
                     96:     uint8_t     parent_uuid[16];
                     97:     uint32_t    parent_timestamp;
                     98:     uint32_t    reserved;
                     99: 
                    100:     // Backing file name (in UTF-16)
                    101:     uint8_t     parent_name[512];
                    102: 
                    103:     struct {
                    104:         uint32_t    platform;
                    105:         uint32_t    data_space;
                    106:         uint32_t    data_length;
                    107:         uint32_t    reserved;
                    108:         uint64_t    data_offset;
                    109:     } parent_locator[8];
                    110: };
                    111: 
                    112: typedef struct BDRVVPCState {
                    113:     uint8_t footer_buf[HEADER_SIZE];
                    114:     uint64_t free_data_block_offset;
                    115:     int max_table_entries;
                    116:     uint32_t *pagetable;
                    117:     uint64_t bat_offset;
                    118:     uint64_t last_bitmap_offset;
                    119: 
                    120:     uint32_t block_size;
                    121:     uint32_t bitmap_size;
                    122: 
                    123: #ifdef CACHE
                    124:     uint8_t *pageentry_u8;
                    125:     uint32_t *pageentry_u32;
                    126:     uint16_t *pageentry_u16;
                    127: 
                    128:     uint64_t last_bitmap;
                    129: #endif
                    130: } BDRVVPCState;
                    131: 
                    132: static uint32_t vpc_checksum(uint8_t* buf, size_t size)
                    133: {
                    134:     uint32_t res = 0;
                    135:     int i;
                    136: 
                    137:     for (i = 0; i < size; i++)
                    138:         res += buf[i];
                    139: 
                    140:     return ~res;
                    141: }
                    142: 
                    143: 
                    144: static int vpc_probe(const uint8_t *buf, int buf_size, const char *filename)
                    145: {
                    146:     if (buf_size >= 8 && !strncmp((char *)buf, "conectix", 8))
                    147:        return 100;
                    148:     return 0;
                    149: }
                    150: 
1.1.1.4   root      151: static int vpc_open(BlockDriverState *bs, int flags)
1.1       root      152: {
                    153:     BDRVVPCState *s = bs->opaque;
1.1.1.4   root      154:     int i;
1.1       root      155:     struct vhd_footer* footer;
                    156:     struct vhd_dyndisk_header* dyndisk_header;
                    157:     uint8_t buf[HEADER_SIZE];
                    158:     uint32_t checksum;
                    159: 
1.1.1.4   root      160:     if (bdrv_pread(bs->file, 0, s->footer_buf, HEADER_SIZE) != HEADER_SIZE)
1.1       root      161:         goto fail;
                    162: 
                    163:     footer = (struct vhd_footer*) s->footer_buf;
                    164:     if (strncmp(footer->creator, "conectix", 8))
                    165:         goto fail;
                    166: 
                    167:     checksum = be32_to_cpu(footer->checksum);
                    168:     footer->checksum = 0;
                    169:     if (vpc_checksum(s->footer_buf, HEADER_SIZE) != checksum)
                    170:         fprintf(stderr, "block-vpc: The header checksum of '%s' is "
1.1.1.4   root      171:             "incorrect.\n", bs->filename);
1.1       root      172: 
                    173:     // The visible size of a image in Virtual PC depends on the geometry
                    174:     // rather than on the size stored in the footer (the size in the footer
                    175:     // is too large usually)
                    176:     bs->total_sectors = (int64_t)
                    177:         be16_to_cpu(footer->cyls) * footer->heads * footer->secs_per_cyl;
                    178: 
1.1.1.4   root      179:     if (bdrv_pread(bs->file, be64_to_cpu(footer->data_offset), buf, HEADER_SIZE)
1.1       root      180:             != HEADER_SIZE)
                    181:         goto fail;
                    182: 
                    183:     dyndisk_header = (struct vhd_dyndisk_header*) buf;
                    184: 
                    185:     if (strncmp(dyndisk_header->magic, "cxsparse", 8))
                    186:         goto fail;
                    187: 
                    188: 
                    189:     s->block_size = be32_to_cpu(dyndisk_header->block_size);
                    190:     s->bitmap_size = ((s->block_size / (8 * 512)) + 511) & ~511;
                    191: 
                    192:     s->max_table_entries = be32_to_cpu(dyndisk_header->max_table_entries);
                    193:     s->pagetable = qemu_malloc(s->max_table_entries * 4);
                    194: 
                    195:     s->bat_offset = be64_to_cpu(dyndisk_header->table_offset);
1.1.1.4   root      196:     if (bdrv_pread(bs->file, s->bat_offset, s->pagetable,
1.1       root      197:             s->max_table_entries * 4) != s->max_table_entries * 4)
                    198:            goto fail;
                    199: 
                    200:     s->free_data_block_offset =
                    201:         (s->bat_offset + (s->max_table_entries * 4) + 511) & ~511;
                    202: 
                    203:     for (i = 0; i < s->max_table_entries; i++) {
                    204:         be32_to_cpus(&s->pagetable[i]);
                    205:         if (s->pagetable[i] != 0xFFFFFFFF) {
                    206:             int64_t next = (512 * (int64_t) s->pagetable[i]) +
                    207:                 s->bitmap_size + s->block_size;
                    208: 
                    209:             if (next> s->free_data_block_offset)
                    210:                 s->free_data_block_offset = next;
                    211:         }
                    212:     }
                    213: 
                    214:     s->last_bitmap_offset = (int64_t) -1;
                    215: 
                    216: #ifdef CACHE
                    217:     s->pageentry_u8 = qemu_malloc(512);
                    218:     s->pageentry_u32 = s->pageentry_u8;
                    219:     s->pageentry_u16 = s->pageentry_u8;
                    220:     s->last_pagetable = -1;
                    221: #endif
                    222: 
                    223:     return 0;
                    224:  fail:
                    225:     return -1;
                    226: }
                    227: 
                    228: /*
                    229:  * Returns the absolute byte offset of the given sector in the image file.
                    230:  * If the sector is not allocated, -1 is returned instead.
                    231:  *
                    232:  * The parameter write must be 1 if the offset will be used for a write
                    233:  * operation (the block bitmaps is updated then), 0 otherwise.
                    234:  */
                    235: static inline int64_t get_sector_offset(BlockDriverState *bs,
                    236:     int64_t sector_num, int write)
                    237: {
                    238:     BDRVVPCState *s = bs->opaque;
                    239:     uint64_t offset = sector_num * 512;
                    240:     uint64_t bitmap_offset, block_offset;
                    241:     uint32_t pagetable_index, pageentry_index;
                    242: 
                    243:     pagetable_index = offset / s->block_size;
                    244:     pageentry_index = (offset % s->block_size) / 512;
                    245: 
                    246:     if (pagetable_index >= s->max_table_entries || s->pagetable[pagetable_index] == 0xffffffff)
                    247:         return -1; // not allocated
                    248: 
                    249:     bitmap_offset = 512 * (uint64_t) s->pagetable[pagetable_index];
                    250:     block_offset = bitmap_offset + s->bitmap_size + (512 * pageentry_index);
                    251: 
                    252:     // We must ensure that we don't write to any sectors which are marked as
                    253:     // unused in the bitmap. We get away with setting all bits in the block
                    254:     // bitmap each time we write to a new block. This might cause Virtual PC to
                    255:     // miss sparse read optimization, but it's not a problem in terms of
                    256:     // correctness.
                    257:     if (write && (s->last_bitmap_offset != bitmap_offset)) {
                    258:         uint8_t bitmap[s->bitmap_size];
                    259: 
                    260:         s->last_bitmap_offset = bitmap_offset;
                    261:         memset(bitmap, 0xff, s->bitmap_size);
1.1.1.4   root      262:         bdrv_pwrite_sync(bs->file, bitmap_offset, bitmap, s->bitmap_size);
1.1       root      263:     }
                    264: 
                    265: //    printf("sector: %" PRIx64 ", index: %x, offset: %x, bioff: %" PRIx64 ", bloff: %" PRIx64 "\n",
                    266: //     sector_num, pagetable_index, pageentry_index,
                    267: //     bitmap_offset, block_offset);
                    268: 
                    269: // disabled by reason
                    270: #if 0
                    271: #ifdef CACHE
                    272:     if (bitmap_offset != s->last_bitmap)
                    273:     {
                    274:        lseek(s->fd, bitmap_offset, SEEK_SET);
                    275: 
                    276:        s->last_bitmap = bitmap_offset;
                    277: 
                    278:        // Scary! Bitmap is stored as big endian 32bit entries,
                    279:        // while we used to look it up byte by byte
                    280:        read(s->fd, s->pageentry_u8, 512);
                    281:        for (i = 0; i < 128; i++)
                    282:            be32_to_cpus(&s->pageentry_u32[i]);
                    283:     }
                    284: 
                    285:     if ((s->pageentry_u8[pageentry_index / 8] >> (pageentry_index % 8)) & 1)
                    286:        return -1;
                    287: #else
                    288:     lseek(s->fd, bitmap_offset + (pageentry_index / 8), SEEK_SET);
                    289: 
                    290:     read(s->fd, &bitmap_entry, 1);
                    291: 
                    292:     if ((bitmap_entry >> (pageentry_index % 8)) & 1)
                    293:        return -1; // not allocated
                    294: #endif
                    295: #endif
                    296: 
                    297:     return block_offset;
                    298: }
                    299: 
                    300: /*
                    301:  * Writes the footer to the end of the image file. This is needed when the
                    302:  * file grows as it overwrites the old footer
                    303:  *
                    304:  * Returns 0 on success and < 0 on error
                    305:  */
                    306: static int rewrite_footer(BlockDriverState* bs)
                    307: {
                    308:     int ret;
                    309:     BDRVVPCState *s = bs->opaque;
                    310:     int64_t offset = s->free_data_block_offset;
                    311: 
1.1.1.4   root      312:     ret = bdrv_pwrite_sync(bs->file, offset, s->footer_buf, HEADER_SIZE);
1.1       root      313:     if (ret < 0)
                    314:         return ret;
                    315: 
                    316:     return 0;
                    317: }
                    318: 
                    319: /*
                    320:  * Allocates a new block. This involves writing a new footer and updating
                    321:  * the Block Allocation Table to use the space at the old end of the image
                    322:  * file (overwriting the old footer)
                    323:  *
                    324:  * Returns the sectors' offset in the image file on success and < 0 on error
                    325:  */
                    326: static int64_t alloc_block(BlockDriverState* bs, int64_t sector_num)
                    327: {
                    328:     BDRVVPCState *s = bs->opaque;
                    329:     int64_t bat_offset;
                    330:     uint32_t index, bat_value;
                    331:     int ret;
                    332:     uint8_t bitmap[s->bitmap_size];
                    333: 
                    334:     // Check if sector_num is valid
                    335:     if ((sector_num < 0) || (sector_num > bs->total_sectors))
                    336:         return -1;
                    337: 
                    338:     // Write entry into in-memory BAT
                    339:     index = (sector_num * 512) / s->block_size;
                    340:     if (s->pagetable[index] != 0xFFFFFFFF)
                    341:         return -1;
                    342: 
                    343:     s->pagetable[index] = s->free_data_block_offset / 512;
                    344: 
                    345:     // Initialize the block's bitmap
                    346:     memset(bitmap, 0xff, s->bitmap_size);
1.1.1.4   root      347:     bdrv_pwrite_sync(bs->file, s->free_data_block_offset, bitmap,
1.1.1.3   root      348:         s->bitmap_size);
1.1       root      349: 
                    350:     // Write new footer (the old one will be overwritten)
                    351:     s->free_data_block_offset += s->block_size + s->bitmap_size;
                    352:     ret = rewrite_footer(bs);
                    353:     if (ret < 0)
                    354:         goto fail;
                    355: 
                    356:     // Write BAT entry to disk
                    357:     bat_offset = s->bat_offset + (4 * index);
                    358:     bat_value = be32_to_cpu(s->pagetable[index]);
1.1.1.4   root      359:     ret = bdrv_pwrite_sync(bs->file, bat_offset, &bat_value, 4);
1.1       root      360:     if (ret < 0)
                    361:         goto fail;
                    362: 
                    363:     return get_sector_offset(bs, sector_num, 0);
                    364: 
                    365: fail:
                    366:     s->free_data_block_offset -= (s->block_size + s->bitmap_size);
                    367:     return -1;
                    368: }
                    369: 
                    370: static int vpc_read(BlockDriverState *bs, int64_t sector_num,
                    371:                     uint8_t *buf, int nb_sectors)
                    372: {
                    373:     BDRVVPCState *s = bs->opaque;
                    374:     int ret;
                    375:     int64_t offset;
1.1.1.4   root      376:     int64_t sectors, sectors_per_block;
1.1       root      377: 
                    378:     while (nb_sectors > 0) {
                    379:         offset = get_sector_offset(bs, sector_num, 0);
                    380: 
1.1.1.4   root      381:         sectors_per_block = s->block_size >> BDRV_SECTOR_BITS;
                    382:         sectors = sectors_per_block - (sector_num % sectors_per_block);
                    383:         if (sectors > nb_sectors) {
                    384:             sectors = nb_sectors;
                    385:         }
                    386: 
1.1       root      387:         if (offset == -1) {
1.1.1.4   root      388:             memset(buf, 0, sectors * BDRV_SECTOR_SIZE);
1.1       root      389:         } else {
1.1.1.4   root      390:             ret = bdrv_pread(bs->file, offset, buf,
                    391:                 sectors * BDRV_SECTOR_SIZE);
                    392:             if (ret != sectors * BDRV_SECTOR_SIZE) {
1.1       root      393:                 return -1;
1.1.1.4   root      394:             }
1.1       root      395:         }
                    396: 
1.1.1.4   root      397:         nb_sectors -= sectors;
                    398:         sector_num += sectors;
                    399:         buf += sectors * BDRV_SECTOR_SIZE;
1.1       root      400:     }
                    401:     return 0;
                    402: }
                    403: 
                    404: static int vpc_write(BlockDriverState *bs, int64_t sector_num,
                    405:     const uint8_t *buf, int nb_sectors)
                    406: {
                    407:     BDRVVPCState *s = bs->opaque;
                    408:     int64_t offset;
1.1.1.4   root      409:     int64_t sectors, sectors_per_block;
1.1       root      410:     int ret;
                    411: 
                    412:     while (nb_sectors > 0) {
                    413:         offset = get_sector_offset(bs, sector_num, 1);
                    414: 
1.1.1.4   root      415:         sectors_per_block = s->block_size >> BDRV_SECTOR_BITS;
                    416:         sectors = sectors_per_block - (sector_num % sectors_per_block);
                    417:         if (sectors > nb_sectors) {
                    418:             sectors = nb_sectors;
                    419:         }
                    420: 
1.1       root      421:         if (offset == -1) {
                    422:             offset = alloc_block(bs, sector_num);
                    423:             if (offset < 0)
                    424:                 return -1;
                    425:         }
                    426: 
1.1.1.4   root      427:         ret = bdrv_pwrite(bs->file, offset, buf, sectors * BDRV_SECTOR_SIZE);
                    428:         if (ret != sectors * BDRV_SECTOR_SIZE) {
1.1       root      429:             return -1;
1.1.1.4   root      430:         }
1.1       root      431: 
1.1.1.4   root      432:         nb_sectors -= sectors;
                    433:         sector_num += sectors;
                    434:         buf += sectors * BDRV_SECTOR_SIZE;
1.1       root      435:     }
                    436: 
                    437:     return 0;
                    438: }
                    439: 
1.1.1.5 ! root      440: static int vpc_flush(BlockDriverState *bs)
        !           441: {
        !           442:     return bdrv_flush(bs->file);
        !           443: }
1.1       root      444: 
                    445: /*
                    446:  * Calculates the number of cylinders, heads and sectors per cylinder
                    447:  * based on a given number of sectors. This is the algorithm described
                    448:  * in the VHD specification.
                    449:  *
                    450:  * Note that the geometry doesn't always exactly match total_sectors but
                    451:  * may round it down.
                    452:  *
                    453:  * Returns 0 on success, -EFBIG if the size is larger than 127 GB
                    454:  */
                    455: static int calculate_geometry(int64_t total_sectors, uint16_t* cyls,
                    456:     uint8_t* heads, uint8_t* secs_per_cyl)
                    457: {
                    458:     uint32_t cyls_times_heads;
                    459: 
                    460:     if (total_sectors > 65535 * 16 * 255)
                    461:         return -EFBIG;
                    462: 
                    463:     if (total_sectors > 65535 * 16 * 63) {
                    464:         *secs_per_cyl = 255;
                    465:         *heads = 16;
                    466:         cyls_times_heads = total_sectors / *secs_per_cyl;
                    467:     } else {
                    468:         *secs_per_cyl = 17;
                    469:         cyls_times_heads = total_sectors / *secs_per_cyl;
                    470:         *heads = (cyls_times_heads + 1023) / 1024;
                    471: 
                    472:         if (*heads < 4)
                    473:             *heads = 4;
                    474: 
                    475:         if (cyls_times_heads >= (*heads * 1024) || *heads > 16) {
                    476:             *secs_per_cyl = 31;
                    477:             *heads = 16;
                    478:             cyls_times_heads = total_sectors / *secs_per_cyl;
                    479:         }
                    480: 
                    481:         if (cyls_times_heads >= (*heads * 1024)) {
                    482:             *secs_per_cyl = 63;
                    483:             *heads = 16;
                    484:             cyls_times_heads = total_sectors / *secs_per_cyl;
                    485:         }
                    486:     }
                    487: 
1.1.1.3   root      488:     *cyls = cyls_times_heads / *heads;
1.1       root      489: 
                    490:     return 0;
                    491: }
                    492: 
                    493: static int vpc_create(const char *filename, QEMUOptionParameter *options)
                    494: {
                    495:     uint8_t buf[1024];
                    496:     struct vhd_footer* footer = (struct vhd_footer*) buf;
                    497:     struct vhd_dyndisk_header* dyndisk_header =
                    498:         (struct vhd_dyndisk_header*) buf;
                    499:     int fd, i;
1.1.1.3   root      500:     uint16_t cyls = 0;
                    501:     uint8_t heads = 0;
                    502:     uint8_t secs_per_cyl = 0;
1.1       root      503:     size_t block_size, num_bat_entries;
                    504:     int64_t total_sectors = 0;
1.1.1.5 ! root      505:     int ret = -EIO;
1.1       root      506: 
                    507:     // Read out options
                    508:     while (options && options->name) {
                    509:         if (!strcmp(options->name, "size")) {
                    510:             total_sectors = options->value.n / 512;
                    511:         }
                    512:         options++;
                    513:     }
                    514: 
                    515:     // Create the file
                    516:     fd = open(filename, O_WRONLY | O_CREAT | O_TRUNC | O_BINARY, 0644);
                    517:     if (fd < 0)
                    518:         return -EIO;
                    519: 
1.1.1.3   root      520:     /* Calculate matching total_size and geometry. Increase the number of
                    521:        sectors requested until we get enough (or fail). */
                    522:     for (i = 0; total_sectors > (int64_t)cyls * heads * secs_per_cyl; i++) {
                    523:         if (calculate_geometry(total_sectors + i,
                    524:                                &cyls, &heads, &secs_per_cyl)) {
1.1.1.5 ! root      525:             ret = -EFBIG;
        !           526:             goto fail;
1.1.1.3   root      527:         }
                    528:     }
1.1       root      529:     total_sectors = (int64_t) cyls * heads * secs_per_cyl;
                    530: 
                    531:     // Prepare the Hard Disk Footer
                    532:     memset(buf, 0, 1024);
                    533: 
1.1.1.2   root      534:     memcpy(footer->creator, "conectix", 8);
1.1       root      535:     // TODO Check if "qemu" creator_app is ok for VPC
1.1.1.2   root      536:     memcpy(footer->creator_app, "qemu", 4);
                    537:     memcpy(footer->creator_os, "Wi2k", 4);
1.1       root      538: 
                    539:     footer->features = be32_to_cpu(0x02);
                    540:     footer->version = be32_to_cpu(0x00010000);
                    541:     footer->data_offset = be64_to_cpu(HEADER_SIZE);
                    542:     footer->timestamp = be32_to_cpu(time(NULL) - VHD_TIMESTAMP_BASE);
                    543: 
                    544:     // Version of Virtual PC 2007
                    545:     footer->major = be16_to_cpu(0x0005);
                    546:     footer->minor =be16_to_cpu(0x0003);
                    547: 
                    548:     footer->orig_size = be64_to_cpu(total_sectors * 512);
                    549:     footer->size = be64_to_cpu(total_sectors * 512);
                    550: 
                    551:     footer->cyls = be16_to_cpu(cyls);
                    552:     footer->heads = heads;
                    553:     footer->secs_per_cyl = secs_per_cyl;
                    554: 
                    555:     footer->type = be32_to_cpu(VHD_DYNAMIC);
                    556: 
                    557:     // TODO uuid is missing
                    558: 
                    559:     footer->checksum = be32_to_cpu(vpc_checksum(buf, HEADER_SIZE));
                    560: 
                    561:     // Write the footer (twice: at the beginning and at the end)
                    562:     block_size = 0x200000;
                    563:     num_bat_entries = (total_sectors + block_size / 512) / (block_size / 512);
                    564: 
1.1.1.5 ! root      565:     if (write(fd, buf, HEADER_SIZE) != HEADER_SIZE) {
        !           566:         goto fail;
        !           567:     }
1.1       root      568: 
1.1.1.5 ! root      569:     if (lseek(fd, 1536 + ((num_bat_entries * 4 + 511) & ~511), SEEK_SET) < 0) {
        !           570:         goto fail;
        !           571:     }
        !           572:     if (write(fd, buf, HEADER_SIZE) != HEADER_SIZE) {
        !           573:         goto fail;
        !           574:     }
1.1       root      575: 
                    576:     // Write the initial BAT
1.1.1.5 ! root      577:     if (lseek(fd, 3 * 512, SEEK_SET) < 0) {
        !           578:         goto fail;
        !           579:     }
1.1       root      580: 
                    581:     memset(buf, 0xFF, 512);
1.1.1.5 ! root      582:     for (i = 0; i < (num_bat_entries * 4 + 511) / 512; i++) {
        !           583:         if (write(fd, buf, 512) != 512) {
        !           584:             goto fail;
        !           585:         }
        !           586:     }
1.1       root      587: 
                    588: 
                    589:     // Prepare the Dynamic Disk Header
                    590:     memset(buf, 0, 1024);
                    591: 
1.1.1.2   root      592:     memcpy(dyndisk_header->magic, "cxsparse", 8);
1.1       root      593: 
                    594:     dyndisk_header->data_offset = be64_to_cpu(0xFFFFFFFF);
                    595:     dyndisk_header->table_offset = be64_to_cpu(3 * 512);
                    596:     dyndisk_header->version = be32_to_cpu(0x00010000);
                    597:     dyndisk_header->block_size = be32_to_cpu(block_size);
                    598:     dyndisk_header->max_table_entries = be32_to_cpu(num_bat_entries);
                    599: 
                    600:     dyndisk_header->checksum = be32_to_cpu(vpc_checksum(buf, 1024));
                    601: 
                    602:     // Write the header
1.1.1.5 ! root      603:     if (lseek(fd, 512, SEEK_SET) < 0) {
        !           604:         goto fail;
        !           605:     }
        !           606: 
        !           607:     if (write(fd, buf, 1024) != 1024) {
        !           608:         goto fail;
        !           609:     }
        !           610:     ret = 0;
1.1       root      611: 
1.1.1.5 ! root      612:  fail:
1.1       root      613:     close(fd);
1.1.1.5 ! root      614:     return ret;
1.1       root      615: }
                    616: 
                    617: static void vpc_close(BlockDriverState *bs)
                    618: {
                    619:     BDRVVPCState *s = bs->opaque;
                    620:     qemu_free(s->pagetable);
                    621: #ifdef CACHE
                    622:     qemu_free(s->pageentry_u8);
                    623: #endif
                    624: }
                    625: 
                    626: static QEMUOptionParameter vpc_create_options[] = {
                    627:     {
                    628:         .name = BLOCK_OPT_SIZE,
                    629:         .type = OPT_SIZE,
                    630:         .help = "Virtual disk size"
                    631:     },
                    632:     { NULL }
                    633: };
                    634: 
                    635: static BlockDriver bdrv_vpc = {
1.1.1.5 ! root      636:     .format_name    = "vpc",
        !           637:     .instance_size  = sizeof(BDRVVPCState),
        !           638:     .bdrv_probe     = vpc_probe,
        !           639:     .bdrv_open      = vpc_open,
        !           640:     .bdrv_read      = vpc_read,
        !           641:     .bdrv_write     = vpc_write,
        !           642:     .bdrv_flush     = vpc_flush,
        !           643:     .bdrv_close     = vpc_close,
        !           644:     .bdrv_create    = vpc_create,
1.1       root      645: 
                    646:     .create_options = vpc_create_options,
                    647: };
                    648: 
                    649: static void bdrv_vpc_init(void)
                    650: {
                    651:     bdrv_register(&bdrv_vpc);
                    652: }
                    653: 
                    654: block_init(bdrv_vpc_init);

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