plugins/floppy/virtual-floppy.h

   1 /* nbdkit
   2  * Copyright Red Hat
   3  *
   4  * Redistribution and use in source and binary forms, with or without
   5  * modification, are permitted provided that the following conditions are
   6  * met:
   7  *
   8  * * Redistributions of source code must retain the above copyright
   9  * notice, this list of conditions and the following disclaimer.
  10  *
  11  * * Redistributions in binary form must reproduce the above copyright
  12  * notice, this list of conditions and the following disclaimer in the
  13  * documentation and/or other materials provided with the distribution.
  14  *
  15  * * Neither the name of Red Hat nor the names of its contributors may be
  16  * used to endorse or promote products derived from this software without
  17  * specific prior written permission.
  18  *
  19  * THIS SOFTWARE IS PROVIDED BY RED HAT AND CONTRIBUTORS ''AS IS'' AND
  20  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO,
  21  * THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A
  22  * PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL RED HAT OR
  23  * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
  24  * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
  25  * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF
  26  * USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
  27  * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
  28  * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
  29  * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  30  * SUCH DAMAGE.
  31  */
  32
  33 #ifndef NBDKIT_VIRTUAL_FLOPPY_H
  34 #define NBDKIT_VIRTUAL_FLOPPY_H
  35
  36 #include <sys/types.h>
  37 #include <sys/stat.h>
  38
  39 #include "regions.h"
  40 #include "vector.h"
  41
  42 DEFINE_VECTOR_TYPE (idxs, size_t);
  43
  44 struct partition_entry {
  45   uint8_t bootable;             /* 0x00 or 0x80 if bootable */
  46   uint8_t chs[3];               /* always set to chs_too_large */
  47   uint8_t part_type;            /* partition type byte - 0x0C = FAT32 with LBA*/
  48   uint8_t chs2[3];              /* always set to chs_too_large */
  49   uint32_t start_sector;        /* 2048 */
  50   uint32_t num_sectors;
  51 } __attribute__ ((packed));
  52
  53 struct bootsector {
  54   uint8_t jmp_insn[3];
  55   uint8_t oem_name[8];                 /* 0x0003 */
  56
  57   /* BIOS Parameter Block, only required for first sector of FAT. */
  58   uint16_t bytes_per_sector;           /* 0x000B */
  59   uint8_t sectors_per_cluster;         /* 0x000D */
  60   uint16_t reserved_sectors;           /* 0x000E */
  61   uint8_t nr_fats;                     /* 0x0010 */
  62   uint16_t nr_root_dir_entries;        /* 0x0011 - always 0 for FAT32 */
  63   uint16_t old_nr_sectors;             /* 0x0013 - always 0 */
  64   uint8_t media_descriptor;            /* 0x0015 - always 0xF8 */
  65   uint16_t old_sectors_per_fat;        /* 0x0016 */
  66   uint16_t sectors_per_track;          /* 0x0018 - always 0 for LBA */
  67   uint16_t nr_heads;                   /* 0x001A - always 0 for LBA */
  68   uint32_t nr_hidden_sectors;          /* 0x001C */
  69   uint32_t nr_sectors;                 /* 0x0020 */
  70
  71   /* FAT32 Extended BIOS Parameter Block. */
  72   uint32_t sectors_per_fat;            /* 0x0024 */
  73   uint16_t mirroring;                  /* 0x0028 */
  74   uint16_t fat_version;                /* 0x002A */
  75   uint32_t root_directory_cluster;     /* 0x002C */
  76   uint16_t fsinfo_sector;              /* 0x0030 */
  77   uint16_t backup_bootsect;            /* 0x0032 */
  78   uint8_t reserved[12];                /* 0x0034 */
  79   uint8_t physical_drive_number;       /* 0x0040 */
  80   uint8_t unused;                      /* 0x0041 */
  81   uint8_t extended_boot_signature;     /* 0x0042 */
  82   uint32_t volume_id;                  /* 0x0043 */
  83   uint8_t volume_label[11];            /* 0x0047 */
  84   uint8_t fstype[8];                   /* 0x0052 - "FAT32   " */
  85
  86   uint8_t unused2[350];
  87
  88   /* Partition table.  Not present in first sector of filesystem. */
  89   uint32_t disk_signature;             /* 0x01B8 */
  90   uint16_t zero;                       /* 0x01BC - 0x00 0x00 */
  91   struct partition_entry partition[4]; /* 0x01BE - partition table */
  92
  93   uint8_t boot_signature[2];           /* 0x01FE - 0x55 0xAA */
  94 } __attribute__ ((packed));
  95
  96 struct fsinfo {
  97   uint8_t signature[4];         /* 0x52 0x52 0x61 0x41 "RRaA" */
  98   uint8_t reserved[480];
  99   uint8_t signature2[4];        /* 0x72 0x72 0x41 0x61 "rrAa" */
 100   uint32_t free_data_clusters;
 101   uint32_t last_free_cluster;
 102   uint8_t reserved2[12];
 103   uint8_t signature3[4];        /* 0x00 0x00 0x55 0xAA */
 104 } __attribute__ ((packed));
 105
 106 struct file {
 107   char *name;                   /* Filename. */
 108   char *host_path;              /* Path of file on the host. */
 109   struct stat statbuf;          /* stat(2) information, including size. */
 110   uint32_t first_cluster;       /* First cluster containing this file. */
 111   uint32_t nr_clusters;         /* Number of clusters. */
 112 };
 113
 114 DEFINE_VECTOR_TYPE (files, struct file);
 115
 116 /* On disk directory entry (non-LFN). */
 117 struct dir_entry {
 118   uint8_t name[8 + 3];
 119   uint8_t attributes;           /* 0x0B */
 120 #define DIR_ENTRY_READONLY     0x01
 121 #define DIR_ENTRY_HIDDEN       0x02
 122 #define DIR_ENTRY_SYSTEM       0x04
 123 #define DIR_ENTRY_VOLUME_LABEL 0x08
 124 #define DIR_ENTRY_SUBDIRECTORY 0x10
 125 #define DIR_ENTRY_ARCHIVE      0x20
 126   uint8_t unused;               /* 0x0C */
 127   uint8_t ctime_10ms;           /* 0x0D - ctime seconds in 10ms units */
 128   uint16_t ctime;               /* 0x0E */
 129   uint16_t cdate;               /* 0x10 */
 130   uint16_t adate;               /* 0x12 */
 131   uint16_t cluster_hi;          /* 0x14 - first cluster (high word) */
 132   uint16_t mtime;               /* 0x16 */
 133   uint16_t mdate;               /* 0x18 */
 134   uint16_t cluster_lo;          /* 0x1A - first cluster (low word) */
 135   uint32_t size;                /* 0x1C - file size */
 136 } __attribute__ ((packed));
 137
 138 DEFINE_VECTOR_TYPE (dir_entries, struct dir_entry);
 139
 140 /* On disk directory entry (LFN). */
 141 struct lfn_entry {
 142   uint8_t seq;                  /* sequence number */
 143   uint16_t name1[5];            /* first five UTF-16LE characters */
 144   uint8_t attributes;           /* 0x0B - always 0x0F */
 145   uint8_t type;                 /* 0x0C - always 0x00 */
 146   uint8_t checksum;             /* 0x0D - DOS file name checksum */
 147   uint16_t name2[6];            /* next six UTF-16LE characters */
 148   uint16_t cluster_lo;          /* 0x1A - always 0x0000 */
 149   uint16_t name3[2];            /* last two UTF-16LE characters */
 150 } __attribute__ ((packed));
 151
 152 struct dir {
 153   size_t pdi;                   /* Link to parent directory (for root, 0). */
 154   char *name;                   /* Directory name (for root, NULL). */
 155   struct stat statbuf;          /* stat(2) information (for root, zeroes). */
 156   uint32_t first_cluster;       /* First cluster containing this dir. */
 157   uint32_t nr_clusters;         /* Number of clusters. */
 158
 159   /* List of subdirectories.  This is actually a list of indexes
 160    * into the floppy->dirs array.
 161    */
 162   idxs subdirs;
 163
 164   /* List of files in this directory.  This is actually a list of
 165    * indexes into the floppy->files array.
 166    */
 167   idxs fileidxs;
 168
 169   /* On disk directory table. */
 170   dir_entries table;
 171 };
 172
 173 DEFINE_VECTOR_TYPE (dirs, struct dir);
 174
 175 struct virtual_floppy {
 176   /* Virtual disk layout. */
 177   struct regions regions;
 178
 179   /* Disk MBR. */
 180   struct bootsector mbr;
 181
 182   /* Partition boot/first sector (also used for backup copy). */
 183   struct bootsector bootsect;
 184
 185   /* Filesystem information sector. */
 186   struct fsinfo fsinfo;
 187
 188   /* File Allocation Table (also used for second copy). */
 189   uint32_t *fat;
 190
 191   /* All regular files found. */
 192   files files;
 193
 194   /* Directories.  dirs[0] == root directory. */
 195   dirs dirs;
 196
 197   uint64_t fat_entries;         /* Size of FAT (number of 32 bit entries). */
 198   uint64_t fat_clusters;        /* Size of FAT (clusters on disk). */
 199   uint64_t data_size;           /* Size of data region (bytes). */
 200   uint64_t data_clusters;       /* Size of data region (clusters). */
 201   uint64_t data_used_clusters;  /* Size of the used part of the data region. */
 202
 203   /* The disk layout:
 204    * sector 0:          MBR
 205    * sector 2048:       partition first sector
 206    * sector 2049:       filesystem information sector
 207    * sector 2050-2053:  unused (reserved sectors 2-5)
 208    * sector 2054:       backup first sector
 209    * sector 2055-2079:  unused (reserved sectors 7-31)
 210    * sector 2080:       FAT
 211    * fat2_start_sector  FAT (second copy)
 212    * data_start_sector  data region (first cluster is always 2)
 213    * data_last_sector   last sector of data region
 214    */
 215   uint32_t fat2_start_sector;
 216   uint32_t data_start_sector;
 217   uint32_t data_last_sector;
 218 };
 219
 220 #define SECTOR_SIZE 512
 221
 222 /* Don't change SECTORS_PER_CLUSTER without also considering the disk
 223  * layout.  It shouldn't be necessary to change this since this
 224  * supports the maximum possible disk size, and only wastes virtual
 225  * space.
 226  */
 227 #define SECTORS_PER_CLUSTER 32
 228 #define CLUSTER_SIZE (SECTOR_SIZE * SECTORS_PER_CLUSTER)
 229
 230 extern void init_virtual_floppy (struct virtual_floppy *floppy)
 231   __attribute__ ((__nonnull__ (1)));
 232 extern int create_virtual_floppy (const char *dir, const char *label,
 233                                   uint64_t size,
 234                                   struct virtual_floppy *floppy)
 235   __attribute__ ((__nonnull__ (1, 2, 4)));
 236 extern void free_virtual_floppy (struct virtual_floppy *floppy)
 237   __attribute__ ((__nonnull__ (1)));
 238 extern int create_directory (size_t di, const char *label,
 239                              struct virtual_floppy *floppy)
 240   __attribute__ ((__nonnull__ (2, 3)));
 241 extern int update_directory_first_cluster (size_t di,
 242                                            struct virtual_floppy *floppy)
 243   __attribute__ ((__nonnull__ (2)));
 244 extern void pad_string (const char *label, size_t n, uint8_t *out)
 245   __attribute__ ((__nonnull__ (1, 3)));
 246
 247 #endif /* NBDKIT_VIRTUAL_FLOPPY_H */