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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 #include <unistd.h>
  42 #ifdef HAVE_ALLOCA_H
  43 #  include <alloca.h>
  44 #else
  45 #  include <stdlib.h>
  46 #endif
  47
  48 /*
  49  * Reads the header from a WIM file.
  50  *
  51  * @filename
  52  *      Name of the WIM file (for error/debug messages only), or NULL if reading
  53  *      directly from file descriptor.
  54  * @in_fd
  55  *      File descriptor, positioned at offset 0, to read the header from.
  56  * @hdr
  57  *      Structure to read the header into.
  58  *
  59  * Return values:
  60  *      WIMLIB_ERR_SUCCESS (0)
  61  *      WIMLIB_ERR_IMAGE_COUNT
  62  *      WIMLIB_ERR_INVALID_CHUNK_SIZE
  63  *      WIMLIB_ERR_INVALID_PART_NUMBER
  64  *      WIMLIB_ERR_NOT_A_WIM_FILE
  65  *      WIMLIB_ERR_READ
  66  *      WIMLIB_ERR_UNEXPECTED_END_OF_FILE
  67  *      WIMLIB_ERR_UNKNOWN_VERSION
  68  */
  69 int
  70 read_wim_header(const tchar *filename, struct filedes *in_fd,
  71                 struct wim_header *hdr)
  72 {
  73         struct wim_header_disk disk_hdr _aligned_attribute(8);
  74         int ret;
  75         tchar *pipe_str;
  76
  77         wimlib_assert(in_fd->offset == 0);
  78
  79         if (!filename) {
  80                 pipe_str = alloca(40);
  81                 tsprintf(pipe_str, T("[fd %d]"), in_fd->fd);
  82                 filename = pipe_str;
  83         }
  84
  85         BUILD_BUG_ON(sizeof(struct wim_header_disk) != WIM_HEADER_DISK_SIZE);
  86
  87         DEBUG("Reading WIM header from \"%"TS"\"", filename);
  88
  89         ret = full_read(in_fd, &disk_hdr, sizeof(disk_hdr));
  90         if (ret)
  91                 goto read_error;
  92
  93         if (disk_hdr.magic != WIM_MAGIC) {
  94                 if (disk_hdr.magic == PWM_MAGIC) {
  95                         /* Pipable WIM:  Use header at end instead, unless
  96                          * actually reading from a pipe.  */
  97                         if (!in_fd->is_pipe) {
  98                                 lseek(in_fd->fd, -WIM_HEADER_DISK_SIZE, SEEK_END);
  99                                 ret = full_read(in_fd, &disk_hdr, sizeof(disk_hdr));
 100                                 if (ret)
 101                                         goto read_error;
 102                         }
 103                 } else {
 104                         ERROR("\"%"TS"\": Invalid magic characters in header", filename);
 105                         return WIMLIB_ERR_NOT_A_WIM_FILE;
 106                 }
 107         }
 108         hdr->magic = disk_hdr.magic;
 109
 110         if (le32_to_cpu(disk_hdr.hdr_size) != sizeof(struct wim_header_disk)) {
 111                 ERROR("\"%"TS"\": Header size is invalid (%u bytes)",
 112                       filename, le32_to_cpu(disk_hdr.hdr_size));
 113                 return WIMLIB_ERR_INVALID_HEADER;
 114         }
 115
 116         if (le32_to_cpu(disk_hdr.wim_version) != WIM_VERSION) {
 117                 ERROR("\"%"TS"\": The WIM header says the WIM version is %u, "
 118                       "but wimlib only knows about version %u",
 119                       filename, le32_to_cpu(disk_hdr.wim_version), WIM_VERSION);
 120                 if (le32_to_cpu(disk_hdr.wim_flags) & WIM_HDR_FLAG_COMPRESS_LZMS) {
 121                         ERROR("\"%"TS"\": This WIM uses LZMS compression, "
 122                               "which is not supported by wimlib.", filename);
 123                 }
 124                 return WIMLIB_ERR_UNKNOWN_VERSION;
 125         }
 126
 127         hdr->flags = le32_to_cpu(disk_hdr.wim_flags);
 128         if (le32_to_cpu(disk_hdr.chunk_size) != WIM_CHUNK_SIZE &&
 129             (hdr->flags & WIM_HDR_FLAG_COMPRESSION)) {
 130                 ERROR("\"%"TS"\": Unexpected chunk size of %u! Ask the author to "
 131                       "implement support for other chunk sizes.",
 132                       filename, le32_to_cpu(disk_hdr.chunk_size));
 133                 ERROR("(Or it might just be that the WIM header is invalid.)");
 134                 return WIMLIB_ERR_INVALID_CHUNK_SIZE;
 135         }
 136
 137         memcpy(hdr->guid, disk_hdr.guid, WIM_GID_LEN);
 138
 139         hdr->part_number = le16_to_cpu(disk_hdr.part_number);
 140         hdr->total_parts = le16_to_cpu(disk_hdr.total_parts);
 141
 142         if (hdr->total_parts == 0 || hdr->part_number == 0 ||
 143             hdr->part_number > hdr->total_parts)
 144         {
 145                 ERROR("\"%"TS"\": Invalid WIM part number: %hu of %hu",
 146                       filename, hdr->part_number, hdr->total_parts);
 147                 return WIMLIB_ERR_INVALID_PART_NUMBER;
 148         }
 149
 150         hdr->image_count = le32_to_cpu(disk_hdr.image_count);
 151
 152         DEBUG("part_number = %u, total_parts = %u, image_count = %u",
 153               hdr->part_number, hdr->total_parts, hdr->image_count);
 154
 155         if (hdr->image_count >= INT_MAX) {
 156                 ERROR("\"%"TS"\": Invalid image count (%u)",
 157                       filename, hdr->image_count);
 158                 return WIMLIB_ERR_IMAGE_COUNT;
 159         }
 160
 161         get_resource_entry(&disk_hdr.lookup_table_res_entry, &hdr->lookup_table_res_entry);
 162         get_resource_entry(&disk_hdr.xml_data_res_entry, &hdr->xml_res_entry);
 163         get_resource_entry(&disk_hdr.boot_metadata_res_entry, &hdr->boot_metadata_res_entry);
 164         hdr->boot_idx = le32_to_cpu(disk_hdr.boot_idx);
 165         get_resource_entry(&disk_hdr.integrity_table_res_entry, &hdr->integrity);
 166         return 0;
 167
 168 read_error:
 169         ERROR_WITH_ERRNO("\"%"TS"\": Error reading header", filename);
 170         return ret;
 171 }
 172
 173 /* Writes the header for a WIM file at the specified offset.  If the offset
 174  * specified is the current one, the position is advanced by the size of the
 175  * header.  */
 176 int
 177 write_wim_header_at_offset(const struct wim_header *hdr, struct filedes *out_fd,
 178                            off_t offset)
 179 {
 180         struct wim_header_disk disk_hdr _aligned_attribute(8);
 181         int ret;
 182
 183         DEBUG("Writing %sWIM header at offset %"PRIu64,
 184               ((hdr->magic == PWM_MAGIC) ? "pipable " : ""),
 185               offset);
 186
 187         disk_hdr.magic = hdr->magic;
 188         disk_hdr.hdr_size = cpu_to_le32(sizeof(struct wim_header_disk));
 189         disk_hdr.wim_version = cpu_to_le32(WIM_VERSION);
 190         disk_hdr.wim_flags = cpu_to_le32(hdr->flags);
 191         disk_hdr.chunk_size = cpu_to_le32((hdr->flags & WIM_HDR_FLAG_COMPRESSION) ?
 192                                                 WIM_CHUNK_SIZE : 0);
 193         memcpy(disk_hdr.guid, hdr->guid, WIM_GID_LEN);
 194
 195         disk_hdr.part_number = cpu_to_le16(hdr->part_number);
 196         disk_hdr.total_parts = cpu_to_le16(hdr->total_parts);
 197         disk_hdr.image_count = cpu_to_le32(hdr->image_count);
 198         put_resource_entry(&hdr->lookup_table_res_entry, &disk_hdr.lookup_table_res_entry);
 199         put_resource_entry(&hdr->xml_res_entry, &disk_hdr.xml_data_res_entry);
 200         put_resource_entry(&hdr->boot_metadata_res_entry, &disk_hdr.boot_metadata_res_entry);
 201         disk_hdr.boot_idx = cpu_to_le32(hdr->boot_idx);
 202         put_resource_entry(&hdr->integrity, &disk_hdr.integrity_table_res_entry);
 203         memset(disk_hdr.unused, 0, sizeof(disk_hdr.unused));
 204
 205         if (offset == out_fd->offset)
 206                 ret = full_write(out_fd, &disk_hdr, sizeof(disk_hdr));
 207         else
 208                 ret = full_pwrite(out_fd, &disk_hdr, sizeof(disk_hdr), offset);
 209         if (ret)
 210                 ERROR_WITH_ERRNO("Failed to write WIM header");
 211         return ret;
 212 }
 213
 214 /* Writes the header for a WIM file at the output file descriptor's current
 215  * offset.  */
 216 int
 217 write_wim_header(const struct wim_header *hdr, struct filedes *out_fd)
 218 {
 219         return write_wim_header_at_offset(hdr, out_fd, out_fd->offset);
 220 }
 221
 222 /* Update just the wim_flags field. */
 223 int
 224 write_wim_header_flags(u32 hdr_flags, struct filedes *out_fd)
 225 {
 226         le32 flags = cpu_to_le32(hdr_flags);
 227
 228         return full_pwrite(out_fd, &flags, sizeof(flags),
 229                            offsetof(struct wim_header_disk, wim_flags));
 230 }
 231
 232 u32
 233 get_wim_hdr_cflags(int ctype)
 234 {
 235         switch (ctype) {
 236         case WIMLIB_COMPRESSION_TYPE_NONE:
 237                 return 0;
 238         case WIMLIB_COMPRESSION_TYPE_LZX:
 239                 return WIM_HDR_FLAG_COMPRESSION | WIM_HDR_FLAG_COMPRESS_LZX;
 240         case WIMLIB_COMPRESSION_TYPE_XPRESS:
 241                 return WIM_HDR_FLAG_COMPRESSION | WIM_HDR_FLAG_COMPRESS_XPRESS;
 242         case WIMLIB_COMPRESSION_TYPE_INVALID:
 243                 break;
 244         }
 245         return (u32)~0U;
 246 }
 247
 248 /*
 249  * Initializes the header for a WIM file.
 250  */
 251 int
 252 init_wim_header(struct wim_header *hdr, int ctype)
 253 {
 254         memset(hdr, 0, sizeof(struct wim_header));
 255         hdr->flags = get_wim_hdr_cflags(ctype);
 256         if (hdr->flags == (u32)~0U) {
 257                 ERROR("Invalid compression type specified (%d)", ctype);
 258                 return WIMLIB_ERR_INVALID_COMPRESSION_TYPE;
 259         }
 260         hdr->total_parts = 1;
 261         hdr->part_number = 1;
 262         randomize_byte_array(hdr->guid, sizeof(hdr->guid));
 263         hdr->magic = WIM_MAGIC;
 264         return 0;
 265 }
 266
 267 struct hdr_flag {
 268         u32 flag;
 269         const char *name;
 270 };
 271 struct hdr_flag hdr_flags[] = {
 272         {WIM_HDR_FLAG_RESERVED,         "RESERVED"},
 273         {WIM_HDR_FLAG_COMPRESSION,      "COMPRESSION"},
 274         {WIM_HDR_FLAG_READONLY,         "READONLY"},
 275         {WIM_HDR_FLAG_SPANNED,          "SPANNED"},
 276         {WIM_HDR_FLAG_RESOURCE_ONLY,    "RESOURCE_ONLY"},
 277         {WIM_HDR_FLAG_METADATA_ONLY,    "METADATA_ONLY"},
 278         {WIM_HDR_FLAG_WRITE_IN_PROGRESS,"WRITE_IN_PROGRESS"},
 279         {WIM_HDR_FLAG_RP_FIX,           "RP_FIX"},
 280         {WIM_HDR_FLAG_COMPRESS_RESERVED,"COMPRESS_RESERVED"},
 281         {WIM_HDR_FLAG_COMPRESS_LZX,     "COMPRESS_LZX"},
 282         {WIM_HDR_FLAG_COMPRESS_XPRESS,  "COMPRESS_XPRESS"},
 283 };
 284
 285 /* API function documented in wimlib.h  */
 286 WIMLIBAPI void
 287 wimlib_print_header(const WIMStruct *wim)
 288 {
 289         const struct wim_header *hdr = &wim->hdr;
 290
 291         tprintf(T("Magic Characters            = MSWIM\\000\\000\\000\n"));
 292         tprintf(T("Header Size                 = %u\n"), WIM_HEADER_DISK_SIZE);
 293         tprintf(T("Version                     = 0x%x\n"), WIM_VERSION);
 294
 295         tprintf(T("Flags                       = 0x%x\n"), hdr->flags);
 296         for (size_t i = 0; i < ARRAY_LEN(hdr_flags); i++)
 297                 if (hdr_flags[i].flag & hdr->flags)
 298                         tprintf(T("    WIM_HDR_FLAG_%s is set\n"), hdr_flags[i].name);
 299
 300         tprintf(T("Chunk Size                  = %u\n"), WIM_CHUNK_SIZE);
 301         tfputs (T("GUID                        = "), stdout);
 302         print_byte_field(hdr->guid, WIM_GID_LEN, stdout);
 303         tputchar(T('\n'));
 304         tprintf(T("Part Number                 = %hu\n"), wim->hdr.part_number);
 305         tprintf(T("Total Parts                 = %hu\n"), wim->hdr.total_parts);
 306         tprintf(T("Image Count                 = %u\n"), hdr->image_count);
 307         tprintf(T("Lookup Table Size           = %"PRIu64"\n"),
 308                                 (u64)hdr->lookup_table_res_entry.size);
 309         tprintf(T("Lookup Table Flags          = 0x%hhx\n"),
 310                                 (u8)hdr->lookup_table_res_entry.flags);
 311         tprintf(T("Lookup Table Offset         = %"PRIu64"\n"),
 312                                 hdr->lookup_table_res_entry.offset);
 313         tprintf(T("Lookup Table Original_size  = %"PRIu64"\n"),
 314                                 hdr->lookup_table_res_entry.original_size);
 315         tprintf(T("XML Data Size               = %"PRIu64"\n"),
 316                                 (u64)hdr->xml_res_entry.size);
 317         tprintf(T("XML Data Flags              = 0x%hhx\n"),
 318                                 (u8)hdr->xml_res_entry.flags);
 319         tprintf(T("XML Data Offset             = %"PRIu64"\n"),
 320                                 hdr->xml_res_entry.offset);
 321         tprintf(T("XML Data Original Size      = %"PRIu64"\n"),
 322                                 hdr->xml_res_entry.original_size);
 323         tprintf(T("Boot Metadata Size          = %"PRIu64"\n"),
 324                                 (u64)hdr->boot_metadata_res_entry.size);
 325         tprintf(T("Boot Metadata Flags         = 0x%hhx\n"),
 326                                 (u8)hdr->boot_metadata_res_entry.flags);
 327         tprintf(T("Boot Metadata Offset        = %"PRIu64"\n"),
 328                                 hdr->boot_metadata_res_entry.offset);
 329         tprintf(T("Boot Metadata Original Size = %"PRIu64"\n"),
 330                                 hdr->boot_metadata_res_entry.original_size);
 331         tprintf(T("Boot Index                  = %u\n"), hdr->boot_idx);
 332         tprintf(T("Integrity Size              = %"PRIu64"\n"),
 333                                 (u64)hdr->integrity.size);
 334         tprintf(T("Integrity Flags             = 0x%hhx\n"),
 335                                 (u8)hdr->integrity.flags);
 336         tprintf(T("Integrity Offset            = %"PRIu64"\n"),
 337                                 hdr->integrity.offset);
 338         tprintf(T("Integrity Original_size     = %"PRIu64"\n"),
 339                                 hdr->integrity.original_size);
 340 }