read_wim_header(): Check return value of lseek()
[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 #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  * @wim
52  *      WIM to read the header from.  @wim->in_fd must be positioned at the
53  *      beginning of the file.
54  *
55  * @hdr
56  *      Structure to read the header into.
57  *
58  * Return values:
59  *      WIMLIB_ERR_SUCCESS (0)
60  *      WIMLIB_ERR_IMAGE_COUNT
61  *      WIMLIB_ERR_INVALID_PART_NUMBER
62  *      WIMLIB_ERR_NOT_A_WIM_FILE
63  *      WIMLIB_ERR_READ
64  *      WIMLIB_ERR_UNEXPECTED_END_OF_FILE
65  *      WIMLIB_ERR_UNKNOWN_VERSION
66  */
67 int
68 read_wim_header(WIMStruct *wim, struct wim_header *hdr)
69 {
70         struct wim_header_disk disk_hdr _aligned_attribute(8);
71         struct filedes *in_fd = &wim->in_fd;
72         const tchar *filename = wim->filename;
73         int ret;
74         tchar *pipe_str;
75
76         wimlib_assert(in_fd->offset == 0);
77
78         if (filename == NULL) {
79                 pipe_str = alloca(40);
80                 tsprintf(pipe_str, T("[fd %d]"), in_fd->fd);
81                 filename = pipe_str;
82         }
83
84         BUILD_BUG_ON(sizeof(struct wim_header_disk) != WIM_HEADER_DISK_SIZE);
85
86         DEBUG("Reading WIM header from \"%"TS"\"", filename);
87
88         ret = full_read(in_fd, &disk_hdr, sizeof(disk_hdr));
89         if (ret)
90                 goto read_error;
91
92         hdr->magic = le64_to_cpu(disk_hdr.magic);
93
94         if (hdr->magic != WIM_MAGIC) {
95                 if (hdr->magic == PWM_MAGIC) {
96                         /* Pipable WIM:  Use header at end instead, unless
97                          * actually reading from a pipe.  */
98                         if (!in_fd->is_pipe) {
99                                 ret = WIMLIB_ERR_READ;
100                                 if (-1 == lseek(in_fd->fd, -WIM_HEADER_DISK_SIZE, SEEK_END))
101                                         goto read_error;
102                                 ret = full_read(in_fd, &disk_hdr, sizeof(disk_hdr));
103                                 if (ret)
104                                         goto read_error;
105                         }
106                 } else {
107                         ERROR("\"%"TS"\": Invalid magic characters in header", filename);
108                         return WIMLIB_ERR_NOT_A_WIM_FILE;
109                 }
110         }
111
112         if (le32_to_cpu(disk_hdr.hdr_size) != sizeof(struct wim_header_disk)) {
113                 ERROR("\"%"TS"\": Header size is invalid (%u bytes)",
114                       filename, le32_to_cpu(disk_hdr.hdr_size));
115                 return WIMLIB_ERR_INVALID_HEADER;
116         }
117
118         hdr->wim_version = le32_to_cpu(disk_hdr.wim_version);
119         if (hdr->wim_version != WIM_VERSION_DEFAULT &&
120             hdr->wim_version != WIM_VERSION_PACKED_STREAMS)
121         {
122                 ERROR("\"%"TS"\": Unknown WIM version: %u",
123                       filename, hdr->wim_version);
124                 return WIMLIB_ERR_UNKNOWN_VERSION;
125         }
126
127         hdr->flags = le32_to_cpu(disk_hdr.wim_flags);
128         hdr->chunk_size = le32_to_cpu(disk_hdr.chunk_size);
129         memcpy(hdr->guid, disk_hdr.guid, WIM_GUID_LEN);
130         hdr->part_number = le16_to_cpu(disk_hdr.part_number);
131         hdr->total_parts = le16_to_cpu(disk_hdr.total_parts);
132
133         if (hdr->total_parts == 0 || hdr->part_number == 0 ||
134             hdr->part_number > hdr->total_parts)
135         {
136                 ERROR("\"%"TS"\": Invalid WIM part number: %hu of %hu",
137                       filename, hdr->part_number, hdr->total_parts);
138                 return WIMLIB_ERR_INVALID_PART_NUMBER;
139         }
140
141         hdr->image_count = le32_to_cpu(disk_hdr.image_count);
142
143         DEBUG("part_number = %u, total_parts = %u, image_count = %u",
144               hdr->part_number, hdr->total_parts, hdr->image_count);
145
146         if (unlikely(hdr->image_count > MAX_IMAGES)) {
147                 ERROR("\"%"TS"\": Invalid image count (%u)",
148                       filename, hdr->image_count);
149                 return WIMLIB_ERR_IMAGE_COUNT;
150         }
151
152         get_wim_reshdr(&disk_hdr.lookup_table_reshdr, &hdr->lookup_table_reshdr);
153         get_wim_reshdr(&disk_hdr.xml_data_reshdr, &hdr->xml_data_reshdr);
154         get_wim_reshdr(&disk_hdr.boot_metadata_reshdr, &hdr->boot_metadata_reshdr);
155         hdr->boot_idx = le32_to_cpu(disk_hdr.boot_idx);
156         get_wim_reshdr(&disk_hdr.integrity_table_reshdr, &hdr->integrity_table_reshdr);
157         return 0;
158
159 read_error:
160         ERROR_WITH_ERRNO("\"%"TS"\": Error reading header", filename);
161         return ret;
162 }
163
164 /* Writes the header for a WIM file at the specified offset.  If the offset
165  * specified is the current one, the position is advanced by the size of the
166  * header.  */
167 int
168 write_wim_header_at_offset(const struct wim_header *hdr, struct filedes *out_fd,
169                            off_t offset)
170 {
171         struct wim_header_disk disk_hdr _aligned_attribute(8);
172         int ret;
173
174         DEBUG("Writing %sWIM header at offset %"PRIu64,
175               ((hdr->magic == PWM_MAGIC) ? "pipable " : ""),
176               offset);
177
178         disk_hdr.magic = cpu_to_le64(hdr->magic);
179         disk_hdr.hdr_size = cpu_to_le32(sizeof(struct wim_header_disk));
180         disk_hdr.wim_version = cpu_to_le32(hdr->wim_version);
181         disk_hdr.wim_flags = cpu_to_le32(hdr->flags);
182         if (hdr->flags & WIM_HDR_FLAG_COMPRESSION)
183                 disk_hdr.chunk_size = cpu_to_le32(hdr->chunk_size);
184         else
185                 disk_hdr.chunk_size = 0;
186         memcpy(disk_hdr.guid, hdr->guid, WIM_GUID_LEN);
187
188         disk_hdr.part_number = cpu_to_le16(hdr->part_number);
189         disk_hdr.total_parts = cpu_to_le16(hdr->total_parts);
190         disk_hdr.image_count = cpu_to_le32(hdr->image_count);
191         put_wim_reshdr(&hdr->lookup_table_reshdr, &disk_hdr.lookup_table_reshdr);
192         put_wim_reshdr(&hdr->xml_data_reshdr, &disk_hdr.xml_data_reshdr);
193         put_wim_reshdr(&hdr->boot_metadata_reshdr, &disk_hdr.boot_metadata_reshdr);
194         disk_hdr.boot_idx = cpu_to_le32(hdr->boot_idx);
195         put_wim_reshdr(&hdr->integrity_table_reshdr, &disk_hdr.integrity_table_reshdr);
196         memset(disk_hdr.unused, 0, sizeof(disk_hdr.unused));
197
198         if (offset == out_fd->offset)
199                 ret = full_write(out_fd, &disk_hdr, sizeof(disk_hdr));
200         else
201                 ret = full_pwrite(out_fd, &disk_hdr, sizeof(disk_hdr), offset);
202         if (ret)
203                 ERROR_WITH_ERRNO("Failed to write WIM header");
204         return ret;
205 }
206
207 /* Writes the header for a WIM file at the output file descriptor's current
208  * offset.  */
209 int
210 write_wim_header(const struct wim_header *hdr, struct filedes *out_fd)
211 {
212         return write_wim_header_at_offset(hdr, out_fd, out_fd->offset);
213 }
214
215 /* Update just the wim_flags field. */
216 int
217 write_wim_header_flags(u32 hdr_flags, struct filedes *out_fd)
218 {
219         le32 flags = cpu_to_le32(hdr_flags);
220
221         return full_pwrite(out_fd, &flags, sizeof(flags),
222                            offsetof(struct wim_header_disk, wim_flags));
223 }
224
225 int
226 set_wim_hdr_cflags(int ctype, struct wim_header *hdr)
227 {
228         hdr->flags &= ~(WIM_HDR_FLAG_COMPRESSION |
229                         WIM_HDR_FLAG_COMPRESS_LZX |
230                         WIM_HDR_FLAG_COMPRESS_RESERVED |
231                         WIM_HDR_FLAG_COMPRESS_XPRESS |
232                         WIM_HDR_FLAG_COMPRESS_LZMS |
233                         WIM_HDR_FLAG_COMPRESS_XPRESS_2);
234         switch (ctype) {
235
236         case WIMLIB_COMPRESSION_TYPE_NONE:
237                 return 0;
238
239         case WIMLIB_COMPRESSION_TYPE_LZX:
240                 hdr->flags |= WIM_HDR_FLAG_COMPRESSION | WIM_HDR_FLAG_COMPRESS_LZX;
241                 return 0;
242
243         case WIMLIB_COMPRESSION_TYPE_XPRESS:
244                 hdr->flags |= WIM_HDR_FLAG_COMPRESSION | WIM_HDR_FLAG_COMPRESS_XPRESS;
245                 return 0;
246
247         case WIMLIB_COMPRESSION_TYPE_LZMS:
248                 hdr->flags |= WIM_HDR_FLAG_COMPRESSION | WIM_HDR_FLAG_COMPRESS_LZMS;
249                 return 0;
250
251         default:
252                 return WIMLIB_ERR_INVALID_COMPRESSION_TYPE;
253         }
254 }
255
256 /*
257  * Initializes the header for a WIM file.
258  */
259 int
260 init_wim_header(struct wim_header *hdr, int ctype, u32 chunk_size)
261 {
262         memset(hdr, 0, sizeof(struct wim_header));
263         hdr->magic = WIM_MAGIC;
264
265         if (ctype == WIMLIB_COMPRESSION_TYPE_LZMS)
266                 hdr->wim_version = WIM_VERSION_PACKED_STREAMS;
267         else
268                 hdr->wim_version = WIM_VERSION_DEFAULT;
269         if (set_wim_hdr_cflags(ctype, hdr)) {
270                 ERROR("Invalid compression type specified (%d)", ctype);
271                 return WIMLIB_ERR_INVALID_COMPRESSION_TYPE;
272         }
273         hdr->chunk_size = chunk_size;
274         hdr->total_parts = 1;
275         hdr->part_number = 1;
276         randomize_byte_array(hdr->guid, sizeof(hdr->guid));
277         return 0;
278 }
279
280 struct hdr_flag {
281         u32 flag;
282         const char *name;
283 };
284 struct hdr_flag hdr_flags[] = {
285         {WIM_HDR_FLAG_RESERVED,         "RESERVED"},
286         {WIM_HDR_FLAG_COMPRESSION,      "COMPRESSION"},
287         {WIM_HDR_FLAG_READONLY,         "READONLY"},
288         {WIM_HDR_FLAG_SPANNED,          "SPANNED"},
289         {WIM_HDR_FLAG_RESOURCE_ONLY,    "RESOURCE_ONLY"},
290         {WIM_HDR_FLAG_METADATA_ONLY,    "METADATA_ONLY"},
291         {WIM_HDR_FLAG_WRITE_IN_PROGRESS,"WRITE_IN_PROGRESS"},
292         {WIM_HDR_FLAG_RP_FIX,           "RP_FIX"},
293         {WIM_HDR_FLAG_COMPRESS_RESERVED,"COMPRESS_RESERVED"},
294         {WIM_HDR_FLAG_COMPRESS_LZX,     "COMPRESS_LZX"},
295         {WIM_HDR_FLAG_COMPRESS_XPRESS,  "COMPRESS_XPRESS"},
296         {WIM_HDR_FLAG_COMPRESS_LZMS,    "COMPRESS_LZMS"},
297         {WIM_HDR_FLAG_COMPRESS_XPRESS_2,"COMPRESS_XPRESS_2"},
298 };
299
300 /* API function documented in wimlib.h  */
301 WIMLIBAPI void
302 wimlib_print_header(const WIMStruct *wim)
303 {
304         const struct wim_header *hdr = &wim->hdr;
305
306         tprintf(T("Magic Characters            = MSWIM\\000\\000\\000\n"));
307         tprintf(T("Header Size                 = %u\n"), WIM_HEADER_DISK_SIZE);
308         tprintf(T("Version                     = 0x%x\n"), hdr->wim_version);
309
310         tprintf(T("Flags                       = 0x%x\n"), hdr->flags);
311         for (size_t i = 0; i < ARRAY_LEN(hdr_flags); i++)
312                 if (hdr_flags[i].flag & hdr->flags)
313                         tprintf(T("    WIM_HDR_FLAG_%s is set\n"), hdr_flags[i].name);
314
315         tprintf(T("Chunk Size                  = %u\n"), hdr->chunk_size);
316         tfputs (T("GUID                        = "), stdout);
317         print_byte_field(hdr->guid, WIM_GUID_LEN, stdout);
318         tputchar(T('\n'));
319         tprintf(T("Part Number                 = %hu\n"), hdr->part_number);
320         tprintf(T("Total Parts                 = %hu\n"), hdr->total_parts);
321         tprintf(T("Image Count                 = %u\n"), hdr->image_count);
322         tprintf(T("Lookup Table Size           = %"PRIu64"\n"),
323                                 (u64)hdr->lookup_table_reshdr.size_in_wim);
324         tprintf(T("Lookup Table Flags          = 0x%hhx\n"),
325                                 (u8)hdr->lookup_table_reshdr.flags);
326         tprintf(T("Lookup Table Offset         = %"PRIu64"\n"),
327                                 hdr->lookup_table_reshdr.offset_in_wim);
328         tprintf(T("Lookup Table Original_size  = %"PRIu64"\n"),
329                                 hdr->lookup_table_reshdr.uncompressed_size);
330         tprintf(T("XML Data Size               = %"PRIu64"\n"),
331                                 (u64)hdr->xml_data_reshdr.size_in_wim);
332         tprintf(T("XML Data Flags              = 0x%hhx\n"),
333                                 (u8)hdr->xml_data_reshdr.flags);
334         tprintf(T("XML Data Offset             = %"PRIu64"\n"),
335                                 hdr->xml_data_reshdr.offset_in_wim);
336         tprintf(T("XML Data Original Size      = %"PRIu64"\n"),
337                                 hdr->xml_data_reshdr.uncompressed_size);
338         tprintf(T("Boot Metadata Size          = %"PRIu64"\n"),
339                                 (u64)hdr->boot_metadata_reshdr.size_in_wim);
340         tprintf(T("Boot Metadata Flags         = 0x%hhx\n"),
341                                 (u8)hdr->boot_metadata_reshdr.flags);
342         tprintf(T("Boot Metadata Offset        = %"PRIu64"\n"),
343                                 hdr->boot_metadata_reshdr.offset_in_wim);
344         tprintf(T("Boot Metadata Original Size = %"PRIu64"\n"),
345                                 hdr->boot_metadata_reshdr.uncompressed_size);
346         tprintf(T("Boot Index                  = %u\n"), hdr->boot_idx);
347         tprintf(T("Integrity Size              = %"PRIu64"\n"),
348                                 (u64)hdr->integrity_table_reshdr.size_in_wim);
349         tprintf(T("Integrity Flags             = 0x%hhx\n"),
350                                 (u8)hdr->integrity_table_reshdr.flags);
351         tprintf(T("Integrity Offset            = %"PRIu64"\n"),
352                                 hdr->integrity_table_reshdr.offset_in_wim);
353         tprintf(T("Integrity Original_size     = %"PRIu64"\n"),
354                                 hdr->integrity_table_reshdr.uncompressed_size);
355 }