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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 /*
 232  * Initializes the header for a WIM file.
 233  */
 234 int
 235 init_header(struct wim_header *hdr, int ctype)
 236 {
 237         memset(hdr, 0, sizeof(struct wim_header));
 238         switch (ctype) {
 239         case WIMLIB_COMPRESSION_TYPE_NONE:
 240                 hdr->flags = 0;
 241                 break;
 242         case WIMLIB_COMPRESSION_TYPE_LZX:
 243                 hdr->flags = WIM_HDR_FLAG_COMPRESSION |
 244                              WIM_HDR_FLAG_COMPRESS_LZX;
 245                 break;
 246         case WIMLIB_COMPRESSION_TYPE_XPRESS:
 247                 hdr->flags = WIM_HDR_FLAG_COMPRESSION |
 248                              WIM_HDR_FLAG_COMPRESS_XPRESS;
 249                 break;
 250         default:
 251                 ERROR("Invalid compression type specified (%d)", ctype);
 252                 return WIMLIB_ERR_INVALID_COMPRESSION_TYPE;
 253         }
 254         hdr->total_parts = 1;
 255         hdr->part_number = 1;
 256         randomize_byte_array(hdr->guid, sizeof(hdr->guid));
 257         return 0;
 258 }
 259
 260 struct hdr_flag {
 261         u32 flag;
 262         const char *name;
 263 };
 264 struct hdr_flag hdr_flags[] = {
 265         {WIM_HDR_FLAG_RESERVED,         "RESERVED"},
 266         {WIM_HDR_FLAG_COMPRESSION,      "COMPRESSION"},
 267         {WIM_HDR_FLAG_READONLY,         "READONLY"},
 268         {WIM_HDR_FLAG_SPANNED,          "SPANNED"},
 269         {WIM_HDR_FLAG_RESOURCE_ONLY,    "RESOURCE_ONLY"},
 270         {WIM_HDR_FLAG_METADATA_ONLY,    "METADATA_ONLY"},
 271         {WIM_HDR_FLAG_WRITE_IN_PROGRESS,"WRITE_IN_PROGRESS"},
 272         {WIM_HDR_FLAG_RP_FIX,           "RP_FIX"},
 273         {WIM_HDR_FLAG_COMPRESS_RESERVED,"COMPRESS_RESERVED"},
 274         {WIM_HDR_FLAG_COMPRESS_LZX,     "COMPRESS_LZX"},
 275         {WIM_HDR_FLAG_COMPRESS_XPRESS,  "COMPRESS_XPRESS"},
 276 };
 277
 278 /* Prints information from the header of the WIM file associated with @w. */
 279 WIMLIBAPI void
 280 wimlib_print_header(const WIMStruct *w)
 281 {
 282         const struct wim_header *hdr = &w->hdr;
 283
 284         tprintf(T("Magic Characters            = MSWIM\\000\\000\\000\n"));
 285         tprintf(T("Header Size                 = %u\n"), WIM_HEADER_DISK_SIZE);
 286         tprintf(T("Version                     = 0x%x\n"), WIM_VERSION);
 287
 288         tprintf(T("Flags                       = 0x%x\n"), hdr->flags);
 289         for (size_t i = 0; i < ARRAY_LEN(hdr_flags); i++)
 290                 if (hdr_flags[i].flag & hdr->flags)
 291                         tprintf(T("    WIM_HDR_FLAG_%s is set\n"), hdr_flags[i].name);
 292
 293         tprintf(T("Chunk Size                  = %u\n"), WIM_CHUNK_SIZE);
 294         tfputs (T("GUID                        = "), stdout);
 295         print_byte_field(hdr->guid, WIM_GID_LEN, stdout);
 296         tputchar(T('\n'));
 297         tprintf(T("Part Number                 = %hu\n"), w->hdr.part_number);
 298         tprintf(T("Total Parts                 = %hu\n"), w->hdr.total_parts);
 299         tprintf(T("Image Count                 = %u\n"), hdr->image_count);
 300         tprintf(T("Lookup Table Size           = %"PRIu64"\n"),
 301                                 (u64)hdr->lookup_table_res_entry.size);
 302         tprintf(T("Lookup Table Flags          = 0x%hhx\n"),
 303                                 (u8)hdr->lookup_table_res_entry.flags);
 304         tprintf(T("Lookup Table Offset         = %"PRIu64"\n"),
 305                                 hdr->lookup_table_res_entry.offset);
 306         tprintf(T("Lookup Table Original_size  = %"PRIu64"\n"),
 307                                 hdr->lookup_table_res_entry.original_size);
 308         tprintf(T("XML Data Size               = %"PRIu64"\n"),
 309                                 (u64)hdr->xml_res_entry.size);
 310         tprintf(T("XML Data Flags              = 0x%hhx\n"),
 311                                 (u8)hdr->xml_res_entry.flags);
 312         tprintf(T("XML Data Offset             = %"PRIu64"\n"),
 313                                 hdr->xml_res_entry.offset);
 314         tprintf(T("XML Data Original Size      = %"PRIu64"\n"),
 315                                 hdr->xml_res_entry.original_size);
 316         tprintf(T("Boot Metadata Size          = %"PRIu64"\n"),
 317                                 (u64)hdr->boot_metadata_res_entry.size);
 318         tprintf(T("Boot Metadata Flags         = 0x%hhx\n"),
 319                                 (u8)hdr->boot_metadata_res_entry.flags);
 320         tprintf(T("Boot Metadata Offset        = %"PRIu64"\n"),
 321                                 hdr->boot_metadata_res_entry.offset);
 322         tprintf(T("Boot Metadata Original Size = %"PRIu64"\n"),
 323                                 hdr->boot_metadata_res_entry.original_size);
 324         tprintf(T("Boot Index                  = %u\n"), hdr->boot_idx);
 325         tprintf(T("Integrity Size              = %"PRIu64"\n"),
 326                                 (u64)hdr->integrity.size);
 327         tprintf(T("Integrity Flags             = 0x%hhx\n"),
 328                                 (u8)hdr->integrity.flags);
 329         tprintf(T("Integrity Offset            = %"PRIu64"\n"),
 330                                 hdr->integrity.offset);
 331         tprintf(T("Integrity Original_size     = %"PRIu64"\n"),
 332                                 hdr->integrity.original_size);
 333 }