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   1 /*
   2  * header.c
   3  *
   4  * Read, write, or create a WIM header.
   5  */
   6
   7 /*
   8  * Copyright (C) 2012, 2013 Eric Biggers
   9  *
  10  * This file is part of wimlib, a library for working with WIM files.
  11  *
  12  * wimlib is free software; you can redistribute it and/or modify it under the
  13  * terms of the GNU General Public License as published by the Free
  14  * Software Foundation; either version 3 of the License, or (at your option)
  15  * any later version.
  16  *
  17  * wimlib is distributed in the hope that it will be useful, but WITHOUT ANY
  18  * WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR
  19  * A PARTICULAR PURPOSE. See the GNU General Public License for more
  20  * details.
  21  *
  22  * You should have received a copy of the GNU General Public License
  23  * along with wimlib; if not, see http://www.gnu.org/licenses/.
  24  */
  25
  26 #ifdef HAVE_CONFIG_H
  27 #  include "config.h"
  28 #endif
  29
  30 #include "wimlib.h"
  31 #include "wimlib/assert.h"
  32 #include "wimlib/endianness.h"
  33 #include "wimlib/error.h"
  34 #include "wimlib/file_io.h"
  35 #include "wimlib/header.h"
  36 #include "wimlib/util.h"
  37 #include "wimlib/wim.h"
  38
  39 #include <limits.h>
  40 #include <string.h>
  41
  42 /* WIM magic characters, translated to a single 64-bit little endian number. */
  43 #define WIM_MAGIC \
  44                 cpu_to_le64(((u64)'M' << 0) |           \
  45                             ((u64)'S' << 8) |           \
  46                             ((u64)'W' << 16) |          \
  47                             ((u64)'I' << 24) |          \
  48                             ((u64)'M' << 32) |          \
  49                             ((u64)'\0' << 40) |         \
  50                             ((u64)'\0' << 48) |         \
  51                             ((u64)'\0' << 54))
  52
  53 /* On-disk format of the WIM header. */
  54 struct wim_header_disk {
  55
  56         /* Magic characters "MSWIM\0\0\0" */
  57         le64 magic;
  58
  59         /* Size of the WIM header, in bytes; WIM_HEADER_DISK_SIZE expected
  60          * (currently the only supported value). */
  61         u32 hdr_size;
  62
  63         /* Version of the WIM file; WIM_VERSION expected (currently the only
  64          * supported value). */
  65         u32 wim_version;
  66
  67         /* Flags for the WIM file (WIM_HDR_FLAG_*) */
  68         u32 wim_flags;
  69
  70         /* Uncompressed chunk size of resources in the WIM.  0 if the WIM is
  71          * uncompressed.  If compressed, WIM_CHUNK_SIZE is expected (currently
  72          * the only supported value).  */
  73         u32 chunk_size;
  74
  75         /* Globally unique identifier for the WIM file.  Basically a bunch of
  76          * random bytes. */
  77         u8 guid[WIM_GID_LEN];
  78
  79         /* Number of this WIM part in the split WIM file, indexed from 1, or 1
  80          * if the WIM is not split. */
  81         u16 part_number;
  82
  83         /* Total number of parts of the split WIM file, or 1 if the WIM is not
  84          * split. */
  85         u16 total_parts;
  86
  87         /* Number of images in the WIM. */
  88         u32 image_count;
  89
  90         /* Location and size of the WIM's lookup table. */
  91         struct resource_entry_disk lookup_table_res_entry;
  92
  93         /* Location and size of the WIM's XML data. */
  94         struct resource_entry_disk xml_data_res_entry;
  95
  96         /* Location and size of metadata resource for the bootable image of the
  97          * WIM, or all zeroes if no image is bootable. */
  98         struct resource_entry_disk boot_metadata_res_entry;
  99
 100         /* 1-based index of the bootable image of the WIM, or 0 if no image is
 101          * bootable. */
 102         u32 boot_idx;
 103
 104         /* Location and size of the WIM's integrity table, or all zeroes if the
 105          * WIM has no integrity table.
 106          *
 107          * Note the integrity_table_res_entry here is 4-byte aligned even though
 108          * it would ordinarily be 8-byte aligned--- hence, the _packed_attribute
 109          * on the `struct wim_header_disk' is essential. */
 110         struct resource_entry_disk integrity_table_res_entry;
 111
 112         /* Unused bytes. */
 113         u8 unused[60];
 114 } _packed_attribute;
 115
 116 /* Reads the header from a WIM file.  */
 117 int
 118 read_header(const tchar *filename, int in_fd, struct wim_header *hdr)
 119 {
 120         struct wim_header_disk disk_hdr _aligned_attribute(8);
 121
 122         BUILD_BUG_ON(sizeof(struct wim_header_disk) != WIM_HEADER_DISK_SIZE);
 123
 124         DEBUG("Reading WIM header from \"%"TS"\"", filename);
 125
 126         if (full_pread(in_fd, &disk_hdr, sizeof(disk_hdr), 0) != sizeof(disk_hdr)) {
 127                 ERROR_WITH_ERRNO("\"%"TS"\": Error reading header", filename);
 128                 return WIMLIB_ERR_READ;
 129         }
 130
 131         if (disk_hdr.magic != WIM_MAGIC) {
 132                 ERROR("\"%"TS"\": Invalid magic characters in header", filename);
 133                 return WIMLIB_ERR_NOT_A_WIM_FILE;
 134         }
 135
 136         if (le32_to_cpu(disk_hdr.hdr_size) != sizeof(struct wim_header_disk)) {
 137                 ERROR("\"%"TS"\": Header size is invalid (%u bytes)",
 138                       filename, le32_to_cpu(disk_hdr.hdr_size));
 139                 return WIMLIB_ERR_INVALID_HEADER_SIZE;
 140         }
 141
 142         if (le32_to_cpu(disk_hdr.wim_version) != WIM_VERSION) {
 143                 ERROR("\"%"TS"\": The WIM header says the WIM version is %u, "
 144                       "but wimlib only knows about version %u",
 145                       filename, le32_to_cpu(disk_hdr.wim_version), WIM_VERSION);
 146                 return WIMLIB_ERR_UNKNOWN_VERSION;
 147         }
 148
 149         hdr->flags = le32_to_cpu(disk_hdr.wim_flags);
 150         if (le32_to_cpu(disk_hdr.chunk_size) != WIM_CHUNK_SIZE &&
 151             (hdr->flags & WIM_HDR_FLAG_COMPRESSION)) {
 152                 ERROR("\"%"TS"\": Unexpected chunk size of %u! Ask the author to "
 153                       "implement support for other chunk sizes.",
 154                       filename, le32_to_cpu(disk_hdr.chunk_size));
 155                 ERROR("(Or it might just be that the WIM header is invalid.)");
 156                 return WIMLIB_ERR_INVALID_CHUNK_SIZE;
 157         }
 158
 159         memcpy(hdr->guid, disk_hdr.guid, WIM_GID_LEN);
 160
 161         hdr->part_number = le16_to_cpu(disk_hdr.part_number);
 162         hdr->total_parts = le16_to_cpu(disk_hdr.total_parts);
 163
 164         if (hdr->total_parts == 0 || hdr->part_number == 0 ||
 165             hdr->part_number > hdr->total_parts)
 166         {
 167                 ERROR("\"%"TS"\": Invalid WIM part number: %hu of %hu",
 168                       filename, hdr->part_number, hdr->total_parts);
 169                 return WIMLIB_ERR_INVALID_PART_NUMBER;
 170         }
 171
 172         hdr->image_count = le32_to_cpu(disk_hdr.image_count);
 173
 174         DEBUG("part_number = %u, total_parts = %u, image_count = %u",
 175               hdr->part_number, hdr->total_parts, hdr->image_count);
 176
 177         if (hdr->image_count >= INT_MAX) {
 178                 ERROR("\"%"TS"\": Invalid image count (%u)",
 179                       filename, hdr->image_count);
 180                 return WIMLIB_ERR_IMAGE_COUNT;
 181         }
 182
 183         get_resource_entry(&disk_hdr.lookup_table_res_entry, &hdr->lookup_table_res_entry);
 184         get_resource_entry(&disk_hdr.xml_data_res_entry, &hdr->xml_res_entry);
 185         get_resource_entry(&disk_hdr.boot_metadata_res_entry, &hdr->boot_metadata_res_entry);
 186         hdr->boot_idx = le32_to_cpu(disk_hdr.boot_idx);
 187         get_resource_entry(&disk_hdr.integrity_table_res_entry, &hdr->integrity);
 188         return 0;
 189 }
 190
 191 /*
 192  * Writes the header for a WIM file.
 193  *
 194  * @hdr:        A pointer to a struct wim_header structure that describes the header.
 195  * @out_fd:     The file descriptor to the WIM file, opened for writing.
 196  *
 197  * Returns zero on success, nonzero on failure.
 198  */
 199 int
 200 write_header(const struct wim_header *hdr, int out_fd)
 201 {
 202         struct wim_header_disk disk_hdr _aligned_attribute(8);
 203         DEBUG("Writing WIM header.");
 204
 205         disk_hdr.magic = WIM_MAGIC;
 206         disk_hdr.hdr_size = cpu_to_le32(sizeof(struct wim_header_disk));
 207         disk_hdr.wim_version = cpu_to_le32(WIM_VERSION);
 208         disk_hdr.wim_flags = cpu_to_le32(hdr->flags);
 209         disk_hdr.chunk_size = cpu_to_le32((hdr->flags & WIM_HDR_FLAG_COMPRESSION) ?
 210                                                 WIM_CHUNK_SIZE : 0);
 211         memcpy(disk_hdr.guid, hdr->guid, WIM_GID_LEN);
 212
 213         disk_hdr.part_number = cpu_to_le16(hdr->part_number);
 214         disk_hdr.total_parts = cpu_to_le16(hdr->total_parts);
 215         disk_hdr.image_count = cpu_to_le32(hdr->image_count);
 216         put_resource_entry(&hdr->lookup_table_res_entry, &disk_hdr.lookup_table_res_entry);
 217         put_resource_entry(&hdr->xml_res_entry, &disk_hdr.xml_data_res_entry);
 218         put_resource_entry(&hdr->boot_metadata_res_entry, &disk_hdr.boot_metadata_res_entry);
 219         disk_hdr.boot_idx = cpu_to_le32(hdr->boot_idx);
 220         put_resource_entry(&hdr->integrity, &disk_hdr.integrity_table_res_entry);
 221         memset(disk_hdr.unused, 0, sizeof(disk_hdr.unused));
 222
 223         if (full_pwrite(out_fd, &disk_hdr, sizeof(disk_hdr), 0) != sizeof(disk_hdr)) {
 224                 ERROR_WITH_ERRNO("Failed to write WIM header");
 225                 return WIMLIB_ERR_WRITE;
 226         }
 227         DEBUG("Done writing WIM header");
 228         return 0;
 229 }
 230
 231 /* Update just the wim_flags field. */
 232 int
 233 write_header_flags(u32 hdr_flags, int out_fd)
 234 {
 235         le32 flags = cpu_to_le32(hdr_flags);
 236         if (full_pwrite(out_fd, &flags, sizeof(flags),
 237                         offsetof(struct wim_header_disk, wim_flags)) != sizeof(flags))
 238         {
 239                 return WIMLIB_ERR_WRITE;
 240         } else {
 241                 return 0;
 242         }
 243
 244 }
 245
 246 /* Update just the part_number and total_parts fields. */
 247 int
 248 write_header_part_data(u16 part_number, u16 total_parts, int out_fd)
 249 {
 250         le16 part_data[2] = {
 251                 cpu_to_le16(part_number),
 252                 cpu_to_le16(total_parts),
 253         };
 254         if (full_pwrite(out_fd, &part_data, sizeof(part_data),
 255                         offsetof(struct wim_header_disk, part_number)) != sizeof(part_data))
 256         {
 257                 return WIMLIB_ERR_WRITE;
 258         } else {
 259                 return 0;
 260         }
 261 }
 262
 263 /*
 264  * Initializes the header for a WIM file.
 265  */
 266 int
 267 init_header(struct wim_header *hdr, int ctype)
 268 {
 269         memset(hdr, 0, sizeof(struct wim_header));
 270         switch (ctype) {
 271         case WIMLIB_COMPRESSION_TYPE_NONE:
 272                 hdr->flags = 0;
 273                 break;
 274         case WIMLIB_COMPRESSION_TYPE_LZX:
 275                 hdr->flags = WIM_HDR_FLAG_COMPRESSION |
 276                              WIM_HDR_FLAG_COMPRESS_LZX;
 277                 break;
 278         case WIMLIB_COMPRESSION_TYPE_XPRESS:
 279                 hdr->flags = WIM_HDR_FLAG_COMPRESSION |
 280                              WIM_HDR_FLAG_COMPRESS_XPRESS;
 281                 break;
 282         default:
 283                 ERROR("Invalid compression type specified (%d)", ctype);
 284                 return WIMLIB_ERR_INVALID_COMPRESSION_TYPE;
 285         }
 286         hdr->total_parts = 1;
 287         hdr->part_number = 1;
 288         randomize_byte_array(hdr->guid, sizeof(hdr->guid));
 289         return 0;
 290 }
 291
 292 struct hdr_flag {
 293         u32 flag;
 294         const char *name;
 295 };
 296 struct hdr_flag hdr_flags[] = {
 297         {WIM_HDR_FLAG_RESERVED,         "RESERVED"},
 298         {WIM_HDR_FLAG_COMPRESSION,      "COMPRESSION"},
 299         {WIM_HDR_FLAG_READONLY,         "READONLY"},
 300         {WIM_HDR_FLAG_SPANNED,          "SPANNED"},
 301         {WIM_HDR_FLAG_RESOURCE_ONLY,    "RESOURCE_ONLY"},
 302         {WIM_HDR_FLAG_METADATA_ONLY,    "METADATA_ONLY"},
 303         {WIM_HDR_FLAG_WRITE_IN_PROGRESS,"WRITE_IN_PROGRESS"},
 304         {WIM_HDR_FLAG_RP_FIX,           "RP_FIX"},
 305         {WIM_HDR_FLAG_COMPRESS_RESERVED,"COMPRESS_RESERVED"},
 306         {WIM_HDR_FLAG_COMPRESS_LZX,     "COMPRESS_LZX"},
 307         {WIM_HDR_FLAG_COMPRESS_XPRESS,  "COMPRESS_XPRESS"},
 308 };
 309
 310 /* Prints information from the header of the WIM file associated with @wim. */
 311 WIMLIBAPI void
 312 wimlib_print_header(const WIMStruct *wim)
 313 {
 314         const struct wim_header *hdr = &wim->hdr;
 315
 316         tprintf(T("Magic Characters            = MSWIM\\000\\000\\000\n"));
 317         tprintf(T("Header Size                 = %u\n"), WIM_HEADER_DISK_SIZE);
 318         tprintf(T("Version                     = 0x%x\n"), WIM_VERSION);
 319
 320         tprintf(T("Flags                       = 0x%x\n"), hdr->flags);
 321         for (size_t i = 0; i < ARRAY_LEN(hdr_flags); i++)
 322                 if (hdr_flags[i].flag & hdr->flags)
 323                         tprintf(T("    WIM_HDR_FLAG_%s is set\n"), hdr_flags[i].name);
 324
 325         tprintf(T("Chunk Size                  = %u\n"), WIM_CHUNK_SIZE);
 326         tfputs (T("GUID                        = "), stdout);
 327         print_byte_field(hdr->guid, WIM_GID_LEN, stdout);
 328         tputchar(T('\n'));
 329         tprintf(T("Part Number                 = %hu\n"), wim->hdr.part_number);
 330         tprintf(T("Total Parts                 = %hu\n"), wim->hdr.total_parts);
 331         tprintf(T("Image Count                 = %u\n"), hdr->image_count);
 332         tprintf(T("Lookup Table Size           = %"PRIu64"\n"),
 333                                 (u64)hdr->lookup_table_res_entry.size);
 334         tprintf(T("Lookup Table Flags          = 0x%hhx\n"),
 335                                 (u8)hdr->lookup_table_res_entry.flags);
 336         tprintf(T("Lookup Table Offset         = %"PRIu64"\n"),
 337                                 hdr->lookup_table_res_entry.offset);
 338         tprintf(T("Lookup Table Original_size  = %"PRIu64"\n"),
 339                                 hdr->lookup_table_res_entry.original_size);
 340         tprintf(T("XML Data Size               = %"PRIu64"\n"),
 341                                 (u64)hdr->xml_res_entry.size);
 342         tprintf(T("XML Data Flags              = 0x%hhx\n"),
 343                                 (u8)hdr->xml_res_entry.flags);
 344         tprintf(T("XML Data Offset             = %"PRIu64"\n"),
 345                                 hdr->xml_res_entry.offset);
 346         tprintf(T("XML Data Original Size      = %"PRIu64"\n"),
 347                                 hdr->xml_res_entry.original_size);
 348         tprintf(T("Boot Metadata Size          = %"PRIu64"\n"),
 349                                 (u64)hdr->boot_metadata_res_entry.size);
 350         tprintf(T("Boot Metadata Flags         = 0x%hhx\n"),
 351                                 (u8)hdr->boot_metadata_res_entry.flags);
 352         tprintf(T("Boot Metadata Offset        = %"PRIu64"\n"),
 353                                 hdr->boot_metadata_res_entry.offset);
 354         tprintf(T("Boot Metadata Original Size = %"PRIu64"\n"),
 355                                 hdr->boot_metadata_res_entry.original_size);
 356         tprintf(T("Boot Index                  = %u\n"), hdr->boot_idx);
 357         tprintf(T("Integrity Size              = %"PRIu64"\n"),
 358                                 (u64)hdr->integrity.size);
 359         tprintf(T("Integrity Flags             = 0x%hhx\n"),
 360                                 (u8)hdr->integrity.flags);
 361         tprintf(T("Integrity Offset            = %"PRIu64"\n"),
 362                                 hdr->integrity.offset);
 363         tprintf(T("Integrity Original_size     = %"PRIu64"\n"),
 364                                 hdr->integrity.original_size);
 365 }