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

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.
        !           436:  */
        !           437: static void calculate_geometry(int64_t total_sectors, uint16_t* cyls,
        !           438:     uint8_t* heads, uint8_t* secs_per_cyl)
        !           439: {
        !           440:     uint32_t cyls_times_heads;
        !           441: 
        !           442:     if (total_sectors > 65535 * 16 * 255)
        !           443:         total_sectors = 65535 * 16 * 255;
        !           444: 
        !           445:     if (total_sectors > 65535 * 16 * 63) {
        !           446:         *secs_per_cyl = 255;
        !           447:         *heads = 16;
        !           448:         cyls_times_heads = total_sectors / *secs_per_cyl;
        !           449:     } else {
        !           450:         *secs_per_cyl = 17;
        !           451:         cyls_times_heads = total_sectors / *secs_per_cyl;
        !           452:         *heads = (cyls_times_heads + 1023) / 1024;
        !           453: 
        !           454:         if (*heads < 4)
        !           455:             *heads = 4;
        !           456: 
        !           457:         if (cyls_times_heads >= (*heads * 1024) || *heads > 16) {
        !           458:             *secs_per_cyl = 31;
        !           459:             *heads = 16;
        !           460:             cyls_times_heads = total_sectors / *secs_per_cyl;
        !           461:         }
        !           462: 
        !           463:         if (cyls_times_heads >= (*heads * 1024)) {
        !           464:             *secs_per_cyl = 63;
        !           465:             *heads = 16;
        !           466:             cyls_times_heads = total_sectors / *secs_per_cyl;
        !           467:         }
        !           468:     }
        !           469: 
        !           470:     // Note: Rounding up deviates from the Virtual PC behaviour
        !           471:     // However, we need this to avoid truncating images in qemu-img convert
        !           472:     *cyls = (cyls_times_heads + *heads - 1) / *heads;
        !           473: }
        !           474: 
        !           475: static int vpc_create(const char *filename, int64_t total_sectors,
        !           476:     const char *backing_file, int flags)
        !           477: {
        !           478:     uint8_t buf[1024];
        !           479:     struct vhd_footer* footer = (struct vhd_footer*) buf;
        !           480:     struct vhd_dyndisk_header* dyndisk_header =
        !           481:         (struct vhd_dyndisk_header*) buf;
        !           482:     int fd, i;
        !           483:     uint16_t cyls;
        !           484:     uint8_t heads;
        !           485:     uint8_t secs_per_cyl;
        !           486:     size_t block_size, num_bat_entries;
        !           487: 
        !           488:     if (backing_file != NULL)
        !           489:         return -ENOTSUP;
        !           490: 
        !           491:     fd = open(filename, O_WRONLY | O_CREAT | O_TRUNC | O_BINARY, 0644);
        !           492:     if (fd < 0)
        !           493:         return -EIO;
        !           494: 
        !           495:     // Calculate matching total_size and geometry
        !           496:     calculate_geometry(total_sectors, &cyls, &heads, &secs_per_cyl);
        !           497:     total_sectors = (int64_t) cyls * heads * secs_per_cyl;
        !           498: 
        !           499:     // Prepare the Hard Disk Footer
        !           500:     memset(buf, 0, 1024);
        !           501: 
        !           502:     strncpy(footer->creator, "conectix", 8);
        !           503:     // TODO Check if "qemu" creator_app is ok for VPC
        !           504:     strncpy(footer->creator_app, "qemu", 4);
        !           505:     strncpy(footer->creator_os, "Wi2k", 4);
        !           506: 
        !           507:     footer->features = be32_to_cpu(0x02);
        !           508:     footer->version = be32_to_cpu(0x00010000);
        !           509:     footer->data_offset = be64_to_cpu(HEADER_SIZE);
        !           510:     footer->timestamp = be32_to_cpu(time(NULL) - VHD_TIMESTAMP_BASE);
        !           511: 
        !           512:     // Version of Virtual PC 2007
        !           513:     footer->major = be16_to_cpu(0x0005);
        !           514:     footer->minor =be16_to_cpu(0x0003);
        !           515: 
        !           516:     footer->orig_size = be64_to_cpu(total_sectors * 512);
        !           517:     footer->size = be64_to_cpu(total_sectors * 512);
        !           518: 
        !           519:     footer->cyls = be16_to_cpu(cyls);
        !           520:     footer->heads = heads;
        !           521:     footer->secs_per_cyl = secs_per_cyl;
        !           522: 
        !           523:     footer->type = be32_to_cpu(VHD_DYNAMIC);
        !           524: 
        !           525:     // TODO uuid is missing
        !           526: 
        !           527:     footer->checksum = be32_to_cpu(vpc_checksum(buf, HEADER_SIZE));
        !           528: 
        !           529:     // Write the footer (twice: at the beginning and at the end)
        !           530:     block_size = 0x200000;
        !           531:     num_bat_entries = (total_sectors + block_size / 512) / (block_size / 512);
        !           532: 
        !           533:     if (write(fd, buf, HEADER_SIZE) != HEADER_SIZE)
        !           534:         return -EIO;
        !           535: 
        !           536:     if (lseek(fd, 1536 + ((num_bat_entries * 4 + 511) & ~511), SEEK_SET) < 0)
        !           537:         return -EIO;
        !           538:     if (write(fd, buf, HEADER_SIZE) != HEADER_SIZE)
        !           539:         return -EIO;
        !           540: 
        !           541:     // Write the initial BAT
        !           542:     if (lseek(fd, 3 * 512, SEEK_SET) < 0)
        !           543:         return -EIO;
        !           544: 
        !           545:     memset(buf, 0xFF, 512);
        !           546:     for (i = 0; i < (num_bat_entries * 4 + 511) / 512; i++)
        !           547:         if (write(fd, buf, 512) != 512)
        !           548:             return -EIO;
        !           549: 
        !           550: 
        !           551:     // Prepare the Dynamic Disk Header
        !           552:     memset(buf, 0, 1024);
        !           553: 
        !           554:     strncpy(dyndisk_header->magic, "cxsparse", 8);
        !           555: 
        !           556:     dyndisk_header->data_offset = be64_to_cpu(0xFFFFFFFF);
        !           557:     dyndisk_header->table_offset = be64_to_cpu(3 * 512);
        !           558:     dyndisk_header->version = be32_to_cpu(0x00010000);
        !           559:     dyndisk_header->block_size = be32_to_cpu(block_size);
        !           560:     dyndisk_header->max_table_entries = be32_to_cpu(num_bat_entries);
        !           561: 
        !           562:     dyndisk_header->checksum = be32_to_cpu(vpc_checksum(buf, 1024));
        !           563: 
        !           564:     // Write the header
        !           565:     if (lseek(fd, 512, SEEK_SET) < 0)
        !           566:         return -EIO;
        !           567:     if (write(fd, buf, 1024) != 1024)
        !           568:         return -EIO;
        !           569: 
        !           570:     close(fd);
        !           571:     return 0;
        !           572: }
        !           573: 
1.1       root      574: static void vpc_close(BlockDriverState *bs)
                    575: {
                    576:     BDRVVPCState *s = bs->opaque;
                    577:     qemu_free(s->pagetable);
                    578: #ifdef CACHE
                    579:     qemu_free(s->pageentry_u8);
                    580: #endif
1.1.1.5 ! root      581:     bdrv_delete(s->hd);
1.1       root      582: }
                    583: 
                    584: BlockDriver bdrv_vpc = {
                    585:     "vpc",
                    586:     sizeof(BDRVVPCState),
                    587:     vpc_probe,
                    588:     vpc_open,
                    589:     vpc_read,
1.1.1.5 ! root      590:     vpc_write,
1.1       root      591:     vpc_close,
1.1.1.5 ! root      592:     vpc_create,
1.1       root      593: };

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