0066d75a3ba7b6d9d5db40a506c4fb9b75154327
[wimlib] / src / header.c
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 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,
119             struct wim_header *hdr, int open_flags)
120 {
121         struct wim_header_disk disk_hdr _aligned_attribute(8);
122
123         DEBUG("Reading WIM header from \"%"TS"\"", filename);
124
125         if (full_pread(in_fd, &disk_hdr, sizeof(disk_hdr), 0) != sizeof(disk_hdr)) {
126                 ERROR_WITH_ERRNO("\"%"TS"\": Error reading header", filename);
127                 return WIMLIB_ERR_READ;
128         }
129
130         if (disk_hdr.magic != WIM_MAGIC) {
131                 ERROR("\"%"TS"\": Invalid magic characters in header", filename);
132                 return WIMLIB_ERR_NOT_A_WIM_FILE;
133         }
134
135         BUILD_BUG_ON(sizeof(struct wim_header_disk) != WIM_HEADER_DISK_SIZE);
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         if (!(open_flags & WIMLIB_OPEN_FLAG_SPLIT_OK) && hdr->total_parts != 1)
173         {
174                 ERROR("\"%"TS"\": This WIM is part %u of a %u-part WIM",
175                       filename, hdr->part_number, hdr->total_parts);
176                 return WIMLIB_ERR_SPLIT_UNSUPPORTED;
177         }
178
179         hdr->image_count = le32_to_cpu(disk_hdr.image_count);
180
181         DEBUG("part_number = %u, total_parts = %u, image_count = %u",
182               hdr->part_number, hdr->total_parts, hdr->image_count);
183
184         if (hdr->image_count >= INT_MAX) {
185                 ERROR("\"%"TS"\": Invalid image count (%u)",
186                       filename, hdr->image_count);
187                 return WIMLIB_ERR_IMAGE_COUNT;
188         }
189
190         get_resource_entry(&disk_hdr.lookup_table_res_entry, &hdr->lookup_table_res_entry);
191         get_resource_entry(&disk_hdr.xml_data_res_entry, &hdr->xml_res_entry);
192         get_resource_entry(&disk_hdr.boot_metadata_res_entry, &hdr->boot_metadata_res_entry);
193         hdr->boot_idx = le32_to_cpu(disk_hdr.boot_idx);
194         get_resource_entry(&disk_hdr.integrity_table_res_entry, &hdr->integrity);
195         return 0;
196 }
197
198 /*
199  * Writes the header for a WIM file.
200  *
201  * @hdr:        A pointer to a struct wim_header structure that describes the header.
202  * @out_fd:     The file descriptor to the WIM file, opened for writing.
203  *
204  * Returns zero on success, nonzero on failure.
205  */
206 int
207 write_header(const struct wim_header *hdr, int out_fd)
208 {
209         struct wim_header_disk disk_hdr _aligned_attribute(8);
210         DEBUG("Writing WIM header.");
211
212         disk_hdr.magic = WIM_MAGIC;
213         disk_hdr.hdr_size = cpu_to_le32(sizeof(struct wim_header_disk));
214         disk_hdr.wim_version = cpu_to_le32(WIM_VERSION);
215         disk_hdr.wim_flags = cpu_to_le32(hdr->flags);
216         disk_hdr.chunk_size = cpu_to_le32((hdr->flags & WIM_HDR_FLAG_COMPRESSION) ?
217                                                 WIM_CHUNK_SIZE : 0);
218         memcpy(disk_hdr.guid, hdr->guid, WIM_GID_LEN);
219
220         disk_hdr.part_number = cpu_to_le16(hdr->part_number);
221         disk_hdr.total_parts = cpu_to_le16(hdr->total_parts);
222         disk_hdr.image_count = cpu_to_le32(hdr->image_count);
223         put_resource_entry(&hdr->lookup_table_res_entry, &disk_hdr.lookup_table_res_entry);
224         put_resource_entry(&hdr->xml_res_entry, &disk_hdr.xml_data_res_entry);
225         put_resource_entry(&hdr->boot_metadata_res_entry, &disk_hdr.boot_metadata_res_entry);
226         disk_hdr.boot_idx = cpu_to_le32(hdr->boot_idx);
227         put_resource_entry(&hdr->integrity, &disk_hdr.integrity_table_res_entry);
228         memset(disk_hdr.unused, 0, sizeof(disk_hdr.unused));
229
230         if (full_pwrite(out_fd, &disk_hdr, sizeof(disk_hdr), 0) != sizeof(disk_hdr)) {
231                 ERROR_WITH_ERRNO("Failed to write WIM header");
232                 return WIMLIB_ERR_WRITE;
233         }
234         DEBUG("Done writing WIM header");
235         return 0;
236 }
237
238 /*
239  * Initializes the header for a WIM file.
240  */
241 int
242 init_header(struct wim_header *hdr, int ctype)
243 {
244         memset(hdr, 0, sizeof(struct wim_header));
245         switch (ctype) {
246         case WIMLIB_COMPRESSION_TYPE_NONE:
247                 hdr->flags = 0;
248                 break;
249         case WIMLIB_COMPRESSION_TYPE_LZX:
250                 hdr->flags = WIM_HDR_FLAG_COMPRESSION |
251                              WIM_HDR_FLAG_COMPRESS_LZX;
252                 break;
253         case WIMLIB_COMPRESSION_TYPE_XPRESS:
254                 hdr->flags = WIM_HDR_FLAG_COMPRESSION |
255                              WIM_HDR_FLAG_COMPRESS_XPRESS;
256                 break;
257         default:
258                 ERROR("Invalid compression type specified (%d)", ctype);
259                 return WIMLIB_ERR_INVALID_COMPRESSION_TYPE;
260         }
261         hdr->total_parts = 1;
262         hdr->part_number = 1;
263         randomize_byte_array(hdr->guid, sizeof(hdr->guid));
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 /* Prints information from the header of the WIM file associated with @w. */
286 WIMLIBAPI void
287 wimlib_print_header(const WIMStruct *w)
288 {
289         const struct wim_header *hdr = &w->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"), w->hdr.part_number);
305         tprintf(T("Total Parts                 = %hu\n"), w->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 }