Archipelago » blktap-utils

/*

 * Copyright (c) 2007, XenSource Inc.

 * Copyright (c) 2010, Citrix Systems, Inc.

 * All rights reserved.

 *

 * Redistribution and use in source and binary forms, with or without

 * modification, are permitted provided that the following conditions are met:

 *     * Redistributions of source code must retain the above copyright

 *       notice, this list of conditions and the following disclaimer.

 *     * Redistributions in binary form must reproduce the above copyright

 *       notice, this list of conditions and the following disclaimer in the

 *       documentation and/or other materials provided with the distribution.

 *     * Neither the name of XenSource Inc. nor the names of its contributors

 *       may be used to endorse or promote products derived from this software

 *       without specific prior written permission.

 *

 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS

 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT

 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR

 * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER

 * OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,

 * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,

 * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR

 * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF

 * LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING

 * NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS

 * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.

 */

#ifndef __VHD_H__

#define __VHD_H__

#include <inttypes.h>

#include <uuid/uuid.h>

#define DEBUG 1

/* ---------------------------------------------------------------------- */

/* General definitions.                                                   */

/* ---------------------------------------------------------------------- */

#define VHD_SECTOR_SIZE  512

#define VHD_SECTOR_SHIFT   9

/* ---------------------------------------------------------------------- */

/* This is the generic disk footer, used by all disks.                    */

/* ---------------------------------------------------------------------- */

struct hd_ftr {

  char        cookie[8];       /* Identifies original creator of the disk      */

  uint32_t    features;        /* Feature Support -- see below                 */

  uint32_t    ff_version;      /* (major,minor) version of disk file           */

  uint64_t    data_offset;     /* Abs. offset from SOF to next structure       */

  uint32_t    timestamp;       /* Creation time.  secs since 1/1/2000GMT       */

  char        crtr_app[4];     /* Creator application                          */

  uint32_t    crtr_ver;        /* Creator version (major,minor)                */

  uint32_t    crtr_os;         /* Creator host OS                              */

  uint64_t    orig_size;       /* Size at creation (bytes)                     */

  uint64_t    curr_size;       /* Current size of disk (bytes)                 */

  uint32_t    geometry;        /* Disk geometry                                */

  uint32_t    type;            /* Disk type                                    */

  uint32_t    checksum;        /* 1's comp sum of this struct.                 */

  uuid_t      uuid;            /* Unique disk ID, used for naming parents      */

  char        saved;           /* one-bit -- is this disk/VM in a saved state? */

  char        hidden;          /* tapdisk-specific field: is this vdi hidden?  */

  char        reserved[426];   /* padding                                      */

};

/* VHD cookie string. */

static const char HD_COOKIE[9]  =  "conectix";

/* Feature fields in hd_ftr */

#define HD_NO_FEATURES     0x00000000

#define HD_TEMPORARY       0x00000001 /* disk can be deleted on shutdown */

#define HD_RESERVED        0x00000002 /* NOTE: must always be set        */

/* Version field in hd_ftr */

#define HD_FF_VERSION      0x00010000

/* Known creator OS type fields in hd_ftr.crtr_os */

#define HD_CR_OS_WINDOWS   0x5769326B /* (Wi2k) */

#define HD_CR_OS_MACINTOSH 0x4D616320 /* (Mac ) */

/*

 * version 0.1:  little endian bitmaps

 * version 1.1:  big endian bitmaps; batmap

 * version 1.2:  libvhd

 * version 1.3:  batmap version bump to 1.2

 */

#define VHD_VERSION(major, minor)  (((major) << 16) | ((minor) & 0x0000FFFF))

#define VHD_CURRENT_VERSION        VHD_VERSION(1, 3)

/* Disk geometry accessor macros. */

/* Geometry is a triple of (cylinders (2 bytes), tracks (1 byte), and 

 * secotrs-per-track (1 byte)) 

 */

#define GEOM_GET_CYLS(_g)  (((_g) >> 16) & 0xffff)

#define GEOM_GET_HEADS(_g) (((_g) >> 8)  & 0xff)

#define GEOM_GET_SPT(_g)   ((_g) & 0xff)

#define GEOM_ENCODE(_c, _h, _s) (((_c) << 16) | ((_h) << 8) | (_s))

/* type field in hd_ftr */

#define HD_TYPE_NONE       0

#define HD_TYPE_FIXED      2  /* fixed-allocation disk */

#define HD_TYPE_DYNAMIC    3  /* dynamic disk */

#define HD_TYPE_DIFF       4  /* differencing disk */

#define HD_TYPE_MAX        6

struct prt_loc {

  uint32_t    code;            /* Platform code -- see defines below.          */

  uint32_t    data_space;      /* Number of 512-byte sectors to store locator  */

  uint32_t    data_len;        /* Actual length of parent locator in bytes     */

  uint32_t    res;             /* Must be zero                                 */

  uint64_t    data_offset;     /* Absolute offset of locator data (bytes)      */

};

/* Platform Codes */

#define PLAT_CODE_NONE  0x0

#define PLAT_CODE_WI2R  0x57693272  /* deprecated                         */

#define PLAT_CODE_WI2K  0x5769326B  /* deprecated                         */

#define PLAT_CODE_W2RU  0x57327275  /* Windows relative path (UTF-16)     */

#define PLAT_CODE_W2KU  0x57326B75  /* Windows absolute path (UTF-16)     */

#define PLAT_CODE_MAC   0x4D616320  /* MacOS alias stored as a blob.      */

#define PLAT_CODE_MACX  0x4D616358  /* File URL (UTF-8), see RFC 2396.    */

/* ---------------------------------------------------------------------- */

/* This is the dynamic disk header.                                       */

/* ---------------------------------------------------------------------- */

struct dd_hdr {

  char        cookie[8];       /* Should contain "cxsparse"                    */

  uint64_t    data_offset;     /* Byte offset of next record. (Unused) 0xffs   */

  uint64_t    table_offset;    /* Absolute offset to the BAT.                  */

  uint32_t    hdr_ver;         /* Version of the dd_hdr (major,minor)          */

  uint32_t    max_bat_size;    /* Maximum number of entries in the BAT         */

  uint32_t    block_size;      /* Block size in bytes. Must be power of 2.     */

  uint32_t    checksum;        /* Header checksum.  1's comp of all fields.    */

  uuid_t      prt_uuid;        /* ID of the parent disk.                       */

  uint32_t    prt_ts;          /* Modification time of the parent disk         */

  uint32_t    res1;            /* Reserved.                                    */

  char        prt_name[512];   /* Parent unicode name.                         */

  struct prt_loc loc[8];  /* Parent locator entries.                      */

  char        res2[256];       /* Reserved.                                    */

};

/* VHD cookie string. */

static const char DD_COOKIE[9]  =  "cxsparse";

/* Version field in hd_ftr */

#define DD_VERSION 0x00010000

/* Default blocksize is 2 meg. */

#define DD_BLOCKSIZE_DEFAULT 0x00200000

#define DD_BLK_UNUSED 0xFFFFFFFF

struct dd_batmap_hdr {

  char        cookie[8];       /* should contain "tdbatmap"                    */

  uint64_t    batmap_offset;   /* byte offset to batmap                        */

  uint32_t    batmap_size;     /* batmap size in sectors                       */

  uint32_t    batmap_version;  /* version of batmap                            */

  uint32_t    checksum;        /* batmap checksum -- 1's complement of batmap  */

  char        marker;          /* generic marker field                         */

};

static const char VHD_BATMAP_COOKIE[9] = "tdbatmap";

/*

 * version 1.1: signed char checksum

 */

#define VHD_BATMAP_VERSION(major, minor)  (((major) << 16) | ((minor) & 0x0000FFFF))

#define VHD_BATMAP_CURRENT_VERSION        VHD_BATMAP_VERSION(1, 2)

/* Layout of a dynamic disk:

 *

 * +-------------------------------------------------+

 * | Mirror image of HD footer (hd_ftr) (512 bytes)  |

 * +-------------------------------------------------+

 * | Sparse drive header (dd_hdr) (1024 bytes)       |

 * +-------------------------------------------------+

 * | BAT (Block allocation table)                    |

 * |   - Array of absolute sector offsets into the   |

 * |     file (uint32_t).                            |

 * |   - Rounded up to a sector boundary.            |

 * |   - Unused entries are marked as 0xFFFFFFFF     |

 * |   - max entries in dd_hdr->max_bat_size         |

 * +-------------------------------------------------+

 * | Data Block 0                                    |

 * | Bitmap (padded to 512 byte sector boundary)     |

 * |   - each bit indicates whether the associated   |

 * |     sector within this block is used.           |

 * | Data                                            |

 * |   - power-of-two multiple of sectors.           |

 * |   - default 2MB (4096 * 512)                    |

 * |   - Any entries with zero in bitmap should be   |

 * |     zero on disk                                |

 * +-------------------------------------------------+

 * | Data Block 1                                    |

 * +-------------------------------------------------+

 * | ...                                             |

 * +-------------------------------------------------+

 * | Data Block n                                    |

 * +-------------------------------------------------+

 * | HD Footer (511 bytes)                           |

 * +-------------------------------------------------+

 */

#endif