Annotation of qemu/block-vpc.c, revision 1.1.1.6

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

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