libdvdcss.c 23.8 KB
Newer Older
1
/* libdvdcss.c: DVD reading library.
Sam Hocevar's avatar
 
Sam Hocevar committed
2
 *
3
 * Authors: Stéphane Borel <stef@via.ecp.fr>
4
 *          Sam Hocevar <sam@zoy.org>
5
 *          Håkan Hjort <d95hjort@dtek.chalmers.se>
Sam Hocevar's avatar
 
Sam Hocevar committed
6
 *
7
 * Copyright (C) 1998-2008 VideoLAN
8
 *
9
 * libdvdcss is free software; you can redistribute it and/or modify
Sam Hocevar's avatar
 
Sam Hocevar committed
10
11
12
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
13
 *
14
 * libdvdcss is distributed in the hope that it will be useful,
Sam Hocevar's avatar
 
Sam Hocevar committed
15
16
17
18
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
Diego Biurrun's avatar
Diego Biurrun committed
19
 * You should have received a copy of the GNU General Public License along
20
 * with libdvdcss; if not, write to the Free Software Foundation, Inc.,
Diego Biurrun's avatar
Diego Biurrun committed
21
 * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
22
23
 */

24
/**
25
26
27
28
29
30
31
 * \mainpage libdvdcss developer documentation
 *
 * \section intro Introduction
 *
 * \e libdvdcss is a simple library designed for accessing DVDs like a block
 * device without having to bother about the decryption. The important features
 * are:
32
 * \li portability: Currently supported platforms are GNU/Linux, FreeBSD,
33
34
 *     NetBSD, OpenBSD, BeOS, Mac OS X, Solaris, QNX, OS/2, and Windows
 *     NT 4.0 SP4 (with IE 5.0) or later.
35
 * \li adaptability: Unlike most similar projects, libdvdcss does not require
36
37
 *     the region of your drive to be set and will try its best to read from
 *     the disc even in the case of a region mismatch.
38
 * \li simplicity: A DVD player can be built around the \e libdvdcss API using
39
40
 *     no more than 4 or 5 library calls.
 *
41
 * \e libdvdcss is free software, released under the GNU General Public License.
42
43
44
45
46
47
48
49
50
51
 * This ensures that \e libdvdcss remains free and used only with free
 * software.
 *
 * \section api The libdvdcss API
 *
 * The complete \e libdvdcss programming interface is documented in the
 * dvdcss.h file.
 *
 * \section env Environment variables
 *
52
 * Some environment variables can be used to change the behavior of
53
54
55
 * \e libdvdcss without having to modify the program which uses it. These
 * variables are:
 *
56
 * \li \b DVDCSS_VERBOSE: Sets the verbosity level.
57
58
59
60
 *     - \c 0 outputs no messages at all.
 *     - \c 1 outputs error messages to stderr.
 *     - \c 2 outputs error messages and debug messages to stderr.
 *
61
 * \li \b DVDCSS_METHOD: Sets the authentication and decryption method
62
63
64
65
66
67
68
69
70
71
72
 *     that \e libdvdcss will use to read scrambled discs. Can be one
 *     of \c title, \c key or \c disc.
 *     - \c key is the default method. \e libdvdcss will use a set of
 *       calculated player keys to try and get the disc key. This can fail
 *       if the drive does not recognize any of the player keys.
 *     - \c disc is a fallback method when \c key has failed. Instead of
 *       using player keys, \e libdvdcss will crack the disc key using
 *       a brute force algorithm. This process is CPU intensive and requires
 *       64 MB of memory to store temporary data.
 *     - \c title is the fallback when all other methods have failed. It does
 *       not rely on a key exchange with the DVD drive, but rather uses a
73
 *       crypto attack to guess the title key. In rare cases this may fail
74
 *       because there is not enough encrypted data on the disc to perform
75
 *       a statistical attack, but on the other hand it is the only way to
76
77
78
 *       decrypt a DVD stored on a hard disc, or a DVD with the wrong region
 *       on an RPC2 drive.
 *
79
 * \li \b DVDCSS_RAW_DEVICE: Specify the raw device to use. Exact usage will
80
81
82
83
 *     depend on your operating system, the Linux utility to set up raw devices
 *     is \c raw(8) for instance. Please note that on most operating systems,
 *     using a raw device requires highly aligned buffers: Linux requires a
 *     2048 bytes alignment (which is the size of a DVD sector).
84
 *
85
 * \li \b DVDCSS_CACHE: Specify a directory in which to cache title key
86
87
88
 *     values. This will speed up descrambling of DVDs which are in the
 *     cache. The DVDCSS_CACHE directory is created if it does not exist,
 *     and a subdirectory is created named after the DVD's title or
89
90
91
92
 *     manufacturing date. If DVDCSS_CACHE is not set or is empty, \e libdvdcss
 *     will use the default value which is "${HOME}/.dvdcss/" under Unix and
 *     "C:\Documents and Settings\$USER\Application Data\dvdcss\" under Win32.
 *     The special value "off" disables caching.
93
 */
Sam Hocevar's avatar
 
Sam Hocevar committed
94

95
/*
Sam Hocevar's avatar
 
Sam Hocevar committed
96
 * Preamble
97
 */
Sam Hocevar's avatar
 
Sam Hocevar committed
98
99
100
101
102
103
104
#include "config.h"

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <sys/types.h>
#include <sys/stat.h>
105
106
107
#ifdef HAVE_SYS_PARAM_H
#   include <sys/param.h>
#endif
108
109
110
#ifdef HAVE_PWD_H
#   include <pwd.h>
#endif
Sam Hocevar's avatar
 
Sam Hocevar committed
111
#include <fcntl.h>
112
#include <errno.h>
Sam Hocevar's avatar
 
Sam Hocevar committed
113
114
115
116
117

#ifdef HAVE_UNISTD_H
#   include <unistd.h>
#endif

Christophe Massiot's avatar
Christophe Massiot committed
118
#ifdef HAVE_LIMITS_H
119
120
121
#   include <limits.h>
#endif

122
123
124
125
#if defined(_WIN32_IE) && _WIN32_IE >= 0x500
#   include <shlobj.h>
#endif

Sam Hocevar's avatar
   
Sam Hocevar committed
126
#include "dvdcss/dvdcss.h"
Sam Hocevar's avatar
 
Sam Hocevar committed
127
128
129
130
131

#include "common.h"
#include "css.h"
#include "libdvdcss.h"
#include "ioctl.h"
132
#include "device.h"
Sam Hocevar's avatar
 
Sam Hocevar committed
133

134
#ifdef HAVE_BROKEN_MKDIR
135
#include <direct.h>
136
137
138
#define mkdir(a, b) _mkdir(a)
#endif

139
140
141
142
/**
 * \brief Open a DVD device or directory and return a dvdcss instance.
 *
 * \param psz_target a string containing the target name, for instance
143
 *        "/dev/hdc" or "E:"
144
145
 * \return a handle to a dvdcss instance or NULL on error.
 *
146
147
148
 * Initialize the \e libdvdcss library, open the requested DVD device or
 * directory, and return a handle to be used for all subsequent \e libdvdcss
 * calls. \e libdvdcss checks whether ioctls can be performed on the disc,
149
150
 * and when possible, the disc key is retrieved.
 */
151
LIBDVDCSS_EXPORT dvdcss_t dvdcss_open ( char *psz_target )
Sam Hocevar's avatar
 
Sam Hocevar committed
152
{
153
    char psz_buffer[PATH_MAX];
Sam Hocevar's avatar
 
Sam Hocevar committed
154
155
156
157
    int i_ret;

    char *psz_method = getenv( "DVDCSS_METHOD" );
    char *psz_verbose = getenv( "DVDCSS_VERBOSE" );
158
    char *psz_cache = getenv( "DVDCSS_CACHE" );
159
#ifdef DVDCSS_RAW_OPEN
Sam Hocevar's avatar
 
Sam Hocevar committed
160
161
162
    char *psz_raw_device = getenv( "DVDCSS_RAW_DEVICE" );
#endif

163
    dvdcss_t dvdcss;
Sam Hocevar's avatar
 
Sam Hocevar committed
164

165
166
167
    /*
     *  Allocate the library structure
     */
Sam Hocevar's avatar
 
Sam Hocevar committed
168
169
170
171
172
173
    dvdcss = malloc( sizeof( struct dvdcss_s ) );
    if( dvdcss == NULL )
    {
        return NULL;
    }

174
175
176
    /*
     *  Initialize structure with default values
     */
177
#ifdef DVDCSS_RAW_OPEN
178
    dvdcss->i_raw_fd = -1;
179
#endif
Sam Hocevar's avatar
 
Sam Hocevar committed
180
    dvdcss->p_titles = NULL;
181
    dvdcss->psz_device = strdup( psz_target );
Sam Hocevar's avatar
 
Sam Hocevar committed
182
    dvdcss->psz_error = "no error";
183
    dvdcss->i_method = DVDCSS_METHOD_KEY;
184
    dvdcss->psz_cachefile[0] = '\0';
Sam Hocevar's avatar
 
Sam Hocevar committed
185
    dvdcss->b_debug = 0;
186
    dvdcss->b_errors = 0;
Sam Hocevar's avatar
 
Sam Hocevar committed
187

188
189
190
191
192
    /*
     *  Find verbosity from DVDCSS_VERBOSE environment variable
     */
    if( psz_verbose != NULL )
    {
193
194
        int i = atoi( psz_verbose );

195
        if( i >= 2 ) dvdcss->b_debug = i;
196
        if( i >= 1 ) dvdcss->b_errors = 1;
197
198
199
200
201
    }

    /*
     *  Find method from DVDCSS_METHOD environment variable
     */
Sam Hocevar's avatar
 
Sam Hocevar committed
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
    if( psz_method != NULL )
    {
        if( !strncmp( psz_method, "key", 4 ) )
        {
            dvdcss->i_method = DVDCSS_METHOD_KEY;
        }
        else if( !strncmp( psz_method, "disc", 5 ) )
        {
            dvdcss->i_method = DVDCSS_METHOD_DISC;
        }
        else if( !strncmp( psz_method, "title", 5 ) )
        {
            dvdcss->i_method = DVDCSS_METHOD_TITLE;
        }
        else
        {
218
219
            print_error( dvdcss, "unknown decrypt method, please choose "
                                 "from 'title', 'key' or 'disc'" );
220
            goto error;
Sam Hocevar's avatar
 
Sam Hocevar committed
221
222
223
        }
    }

224
225
226
227
228
    /*
     *  If DVDCSS_CACHE was not set, try to guess a default value
     */
    if( psz_cache == NULL || psz_cache[0] == '\0' )
    {
229
#if defined(_WIN32_IE) && _WIN32_IE >= 0x500
230
231
232
233
        char psz_home[MAX_PATH];

        /* Cache our keys in
         * C:\Documents and Settings\$USER\Application Data\dvdcss\ */
234
235
        if (SHGetFolderPathA (NULL, CSIDL_APPDATA | CSIDL_FLAG_CREATE,
                              NULL, SHGFP_TYPE_CURRENT, psz_home ) == S_OK)
236
        {
237
            snprintf( psz_buffer, PATH_MAX, "%s\\dvdcss", psz_home );
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
            psz_buffer[PATH_MAX-1] = '\0';
            psz_cache = psz_buffer;
        }
#else
        char *psz_home = NULL;
#   ifdef HAVE_PWD_H
        struct passwd *p_pwd;

        /* Try looking in password file for home dir. */
        p_pwd = getpwuid(getuid());
        if( p_pwd )
        {
            psz_home = p_pwd->pw_dir;
        }
#   endif

        if( psz_home == NULL )
        {
            psz_home = getenv( "HOME" );
        }
258
259
260
261
        if( psz_home == NULL )
        {
            psz_home = getenv( "USERPROFILE" );
        }
262
263
264
265

        /* Cache our keys in ${HOME}/.dvdcss/ */
        if( psz_home )
        {
KO Myung-Hun's avatar
KO Myung-Hun committed
266
267
            int home_pos = 0;

268
#ifdef __OS2__
KO Myung-Hun's avatar
KO Myung-Hun committed
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
            if( *psz_home == '/' || *psz_home == '\\')
            {
                char *psz_unixroot = getenv("UNIXROOT");

                if( psz_unixroot &&
                    psz_unixroot[0] &&
                    psz_unixroot[1] == ':'  &&
                    psz_unixroot[2] == '\0')
                {
                    strcpy( psz_buffer, psz_unixroot );
                    home_pos = 2;
                }
            }
#endif
            snprintf( psz_buffer + home_pos, PATH_MAX - home_pos,
                      "%s/.dvdcss", psz_home );
285
286
287
288
289
290
            psz_buffer[PATH_MAX-1] = '\0';
            psz_cache = psz_buffer;
        }
#endif
    }

291
292
293
294
295
    /*
     *  Find cache dir from the DVDCSS_CACHE environment variable
     */
    if( psz_cache != NULL )
    {
296
        if( psz_cache[0] == '\0' || !strcmp( psz_cache, "off" ) )
297
298
299
300
        {
            psz_cache = NULL;
        }
        /* Check that we can add the ID directory and the block filename */
Sam Hocevar's avatar
Sam Hocevar committed
301
302
        else if( strlen( psz_cache ) + 1 + 32 + 1 + (KEY_SIZE * 2) + 10 + 1
                  > PATH_MAX )
303
        {
304
            print_error( dvdcss, "cache directory name is too long" );
305
306
307
308
            psz_cache = NULL;
        }
    }

309
310
311
    /*
     *  Open device
     */
312
313
    dvdcss_check_device( dvdcss );
    i_ret = dvdcss_open_device( dvdcss );
Sam Hocevar's avatar
 
Sam Hocevar committed
314
315
    if( i_ret < 0 )
    {
316
        goto error;
Sam Hocevar's avatar
 
Sam Hocevar committed
317
    }
318

319
    dvdcss->b_scrambled = 1; /* Assume the worst */
320
    dvdcss->b_ioctls = dvdcss_use_ioctls( dvdcss );
Sam Hocevar's avatar
 
Sam Hocevar committed
321

322
    if( dvdcss->b_ioctls )
Sam Hocevar's avatar
 
Sam Hocevar committed
323
    {
324
        i_ret = dvdcss_test( dvdcss );
325

326
        if( i_ret == -3 )
327
        {
328
329
330
            print_debug( dvdcss, "scrambled disc on a region-free RPC-II "
                                 "drive: possible failure, but continuing "
                                 "anyway" );
331
332
        }
        else if( i_ret < 0 )
Sam Hocevar's avatar
Sam Hocevar committed
333
334
        {
            /* Disable the CSS ioctls and hope that it works? */
335
336
            print_debug( dvdcss,
                         "could not check whether the disc was scrambled" );
Sam Hocevar's avatar
Sam Hocevar committed
337
338
339
340
            dvdcss->b_ioctls = 0;
        }
        else
        {
341
342
            print_debug( dvdcss, i_ret ? "disc is scrambled"
                                       : "disc is unscrambled" );
Sam Hocevar's avatar
Sam Hocevar committed
343
344
            dvdcss->b_scrambled = i_ret;
        }
Sam Hocevar's avatar
 
Sam Hocevar committed
345
346
    }

347
    memset( dvdcss->css.p_disc_key, 0, KEY_SIZE );
Sam Hocevar's avatar
 
Sam Hocevar committed
348
    /* If disc is CSS protected and the ioctls work, authenticate the drive */
349
    if( dvdcss->b_scrambled && dvdcss->b_ioctls )
Sam Hocevar's avatar
 
Sam Hocevar committed
350
    {
351
        i_ret = dvdcss_disckey( dvdcss );
Sam Hocevar's avatar
 
Sam Hocevar committed
352
353
354

        if( i_ret < 0 )
        {
355
            print_debug( dvdcss, "could not get disc key" );
Sam Hocevar's avatar
 
Sam Hocevar committed
356
357
358
        }
    }

Sam Hocevar's avatar
Sam Hocevar committed
359
360
361
    /* If the cache is enabled, write the cache directory tag */
    if( psz_cache )
    {
362
363
        static const char psz_tag[] =
            "Signature: 8a477f597d28d172789f06886806bc55\r\n"
Sam Hocevar's avatar
Sam Hocevar committed
364
365
366
            "# This file is a cache directory tag created by libdvdcss.\r\n"
            "# For information about cache directory tags, see:\r\n"
            "#   http://www.brynosaurus.com/cachedir/\r\n";
367
        char psz_tagfile[PATH_MAX + 1 + 12 + 1];
Sam Hocevar's avatar
Sam Hocevar committed
368
369
370
        int i_fd;

        sprintf( psz_tagfile, "%s/CACHEDIR.TAG", psz_cache );
Sam Hocevar's avatar
Sam Hocevar committed
371
        i_fd = open( psz_tagfile, O_RDWR|O_CREAT, 0644 );
Sam Hocevar's avatar
Sam Hocevar committed
372
373
        if( i_fd >= 0 )
        {
374
375
            ssize_t len = strlen(psz_tag);
            if( write( i_fd, psz_tag, len ) < len )
376
377
378
379
            {
                print_error( dvdcss,
                             "Error writing cache directory tag, continuing..\n" );
            }
Sam Hocevar's avatar
Sam Hocevar committed
380
381
382
383
            close( i_fd );
        }
    }

384
385
386
    /* If the cache is enabled, extract a unique disc ID */
    if( psz_cache )
    {
387
        uint8_t p_sector[DVDCSS_BLOCK_SIZE];
388
        char psz_key[1 + KEY_SIZE * 2 + 1];
Ivan Kalvachev's avatar
   
Ivan Kalvachev committed
389
390
        char *psz_title;
        uint8_t *psz_serial;
391
392
        int i;

393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
        /* We read sector 0. If it starts with 0x000001ba (BE), we are
         * reading a VOB file, and we should not cache anything. */

        i_ret = dvdcss->pf_seek( dvdcss, 0 );
        if( i_ret != 0 )
        {
            goto nocache;
        }

        i_ret = dvdcss->pf_read( dvdcss, p_sector, 1 );
        if( i_ret != 1 )
        {
            goto nocache;
        }

        if( p_sector[0] == 0x00 && p_sector[1] == 0x00
             && p_sector[2] == 0x01 && p_sector[3] == 0xba )
        {
            goto nocache;
        }

414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
        /* The data we are looking for is at sector 16 (32768 bytes):
         *  - offset 40: disc title (32 uppercase chars)
         *  - offset 813: manufacturing date + serial no (16 digits) */

        i_ret = dvdcss->pf_seek( dvdcss, 16 );
        if( i_ret != 16 )
        {
            goto nocache;
        }

        i_ret = dvdcss->pf_read( dvdcss, p_sector, 1 );
        if( i_ret != 1 )
        {
            goto nocache;
        }

        /* Get the disc title */
431
        psz_title = (char *)p_sector + 40;
Michael Roitzsch's avatar
   
Michael Roitzsch committed
432
        psz_title[32] = '\0';
433
434
435

        for( i = 0 ; i < 32 ; i++ )
        {
Michael Roitzsch's avatar
   
Michael Roitzsch committed
436
            if( psz_title[i] <= ' ' )
437
            {
Michael Roitzsch's avatar
   
Michael Roitzsch committed
438
                psz_title[i] = '\0';
439
440
                break;
            }
Michael Roitzsch's avatar
   
Michael Roitzsch committed
441
            else if( psz_title[i] == '/' || psz_title[i] == '\\' )
442
            {
Michael Roitzsch's avatar
   
Michael Roitzsch committed
443
                psz_title[i] = '-';
444
445
446
            }
        }

Michael Roitzsch's avatar
   
Michael Roitzsch committed
447
        /* Get the date + serial */
Ivan Kalvachev's avatar
   
Ivan Kalvachev committed
448
        psz_serial = p_sector + 813;
Michael Roitzsch's avatar
   
Michael Roitzsch committed
449
        psz_serial[16] = '\0';
450

Michael Roitzsch's avatar
   
Michael Roitzsch committed
451
452
453
454
        /* Check that all characters are digits, otherwise convert. */
        for( i = 0 ; i < 16 ; i++ )
        {
            if( psz_serial[i] < '0' || psz_serial[i] > '9' )
455
            {
456
                char psz_tmp[16 + 1];
Sam Hocevar's avatar
Sam Hocevar committed
457
458
                sprintf( psz_tmp,
                         "%.2x%.2x%.2x%.2x%.2x%.2x%.2x%.2x",
Michael Roitzsch's avatar
   
Michael Roitzsch committed
459
460
461
                         psz_serial[0], psz_serial[1], psz_serial[2],
                         psz_serial[3], psz_serial[4], psz_serial[5],
                         psz_serial[6], psz_serial[7] );
Sam Hocevar's avatar
Sam Hocevar committed
462
                memcpy( psz_serial, psz_tmp, 16 );
Michael Roitzsch's avatar
   
Michael Roitzsch committed
463
                break;
464
465
466
            }
        }

Sam Hocevar's avatar
Sam Hocevar committed
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
        /* Get disk key, since some discs have got same title, manufacturing
         * date and serial number, but different keys */
        if( dvdcss->b_scrambled )
        {
             psz_key[0] = '-';
             for( i = 0; i < KEY_SIZE; i++ )
             {
                 sprintf( &psz_key[1+i*2], "%.2x", dvdcss->css.p_disc_key[i] );
             }
             psz_key[1 + KEY_SIZE * 2] = '\0';
        }
        else
        {
             psz_key[0] = 0;
        }

483
484
485
486
487
        /* We have a disc name or ID, we can create the cache dir */
        i = sprintf( dvdcss->psz_cachefile, "%s", psz_cache );
        i_ret = mkdir( dvdcss->psz_cachefile, 0755 );
        if( i_ret < 0 && errno != EEXIST )
        {
488
            print_error( dvdcss, "failed creating cache directory" );
489
490
491
492
            dvdcss->psz_cachefile[0] = '\0';
            goto nocache;
        }

Sam Hocevar's avatar
Sam Hocevar committed
493
494
        i += sprintf( dvdcss->psz_cachefile + i, "/%s-%s%s", psz_title,
                      psz_serial, psz_key );
495
496
497
        i_ret = mkdir( dvdcss->psz_cachefile, 0755 );
        if( i_ret < 0 && errno != EEXIST )
        {
498
            print_error( dvdcss, "failed creating cache subdirectory" );
499
500
501
            dvdcss->psz_cachefile[0] = '\0';
            goto nocache;
        }
Christopher Richards's avatar
   
Christopher Richards committed
502
        i += sprintf( dvdcss->psz_cachefile + i, "/");
503
504
505
506

        /* Pointer to the filename we will use. */
        dvdcss->psz_block = dvdcss->psz_cachefile + i;

507
508
        print_debug( dvdcss, "using CSS key cache dir: %s",
                             dvdcss->psz_cachefile );
509
510
511
    }
    nocache:

512
#ifdef DVDCSS_RAW_OPEN
Michael Roitzsch's avatar
   
Michael Roitzsch committed
513
514
    if( psz_raw_device != NULL )
    {
515
        dvdcss_raw_open( dvdcss, psz_raw_device );
Michael Roitzsch's avatar
   
Michael Roitzsch committed
516
517
518
    }
#endif

519
520
521
    /* Seek at the beginning, just for safety. */
    dvdcss->pf_seek( dvdcss, 0 );

Sam Hocevar's avatar
 
Sam Hocevar committed
522
    return dvdcss;
523
524
525
526
527

error:
    free( dvdcss->psz_device );
    free( dvdcss );
    return NULL;
Sam Hocevar's avatar
 
Sam Hocevar committed
528
529
}

530
/**
531
 * \brief Return a string containing the last error that occurred in the
532
533
 *        given \e libdvdcss instance.
 *
534
535
 * \param dvdcss a \e libdvdcss instance
 * \return a NULL-terminated string containing the last error message.
536
 *
537
538
 * Return a string with the last error message produced by \e libdvdcss.
 * Useful to conveniently format error messages in external applications.
539
 */
540
LIBDVDCSS_EXPORT char * dvdcss_error ( dvdcss_t dvdcss )
Sam Hocevar's avatar
 
Sam Hocevar committed
541
542
543
544
{
    return dvdcss->psz_error;
}

545
546
547
/**
 * \brief Seek in the disc and change the current key if requested.
 *
548
549
 * \param dvdcss a \e libdvdcss instance
 * \param i_blocks an absolute block offset to seek to
550
 * \param i_flags #DVDCSS_NOFLAGS, optionally ORed with one of #DVDCSS_SEEK_KEY
551
552
 *        or #DVDCSS_SEEK_MPEG
 * \return the new position in blocks or a negative value in case an error
553
554
555
556
557
558
559
 *         happened.
 *
 * This function seeks to the requested position, in logical blocks.
 *
 * You typically set \p i_flags to #DVDCSS_NOFLAGS when seeking in a .IFO.
 *
 * If #DVDCSS_SEEK_MPEG is specified in \p i_flags and if \e libdvdcss finds it
560
 * reasonable to do so (i.e., if the dvdcss method is not "title"), the current
561
 * title key will be checked and a new one will be calculated if necessary.
562
 * This flag is typically used when reading data from a .VOB file.
563
 *
564
 * If #DVDCSS_SEEK_KEY is specified, the title key will always be checked,
565
 * even with the "title" method. This flag is typically used when seeking
566
567
 * in a new title.
 */
568
LIBDVDCSS_EXPORT int dvdcss_seek ( dvdcss_t dvdcss, int i_blocks, int i_flags )
Sam Hocevar's avatar
 
Sam Hocevar committed
569
570
571
{
    /* title cracking method is too slow to be used at each seek */
    if( ( ( i_flags & DVDCSS_SEEK_MPEG )
572
             && ( dvdcss->i_method != DVDCSS_METHOD_TITLE ) )
Sam Hocevar's avatar
 
Sam Hocevar committed
573
574
575
       || ( i_flags & DVDCSS_SEEK_KEY ) )
    {
        /* check the title key */
576
        if( dvdcss_title( dvdcss, i_blocks ) )
Sam Hocevar's avatar
 
Sam Hocevar committed
577
578
579
580
581
        {
            return -1;
        }
    }

582
    return dvdcss->pf_seek( dvdcss, i_blocks );
Sam Hocevar's avatar
 
Sam Hocevar committed
583
584
}

585
586
587
/**
 * \brief Read from the disc and decrypt data if requested.
 *
588
589
590
591
592
 * \param dvdcss a \e libdvdcss instance
 * \param p_buffer a buffer that will contain the data read from the disc
 * \param i_blocks the amount of blocks to read
 * \param i_flags #DVDCSS_NOFLAGS, optionally ORed with #DVDCSS_READ_DECRYPT
 * \return the amount of blocks read or a negative value in case an
593
594
 *         error happened.
 *
595
 * Read \p i_blocks logical blocks from the DVD.
596
597
598
599
600
601
602
 *
 * You typically set \p i_flags to #DVDCSS_NOFLAGS when reading data from a
 * .IFO file on the DVD.
 *
 * If #DVDCSS_READ_DECRYPT is specified in \p i_flags, dvdcss_read() will
 * automatically decrypt scrambled sectors. This flag is typically used when
 * reading data from a .VOB file on the DVD. It has no effect on unscrambled
603
 * discs or unscrambled sectors and can be safely used on those.
604
605
 *
 * \warning dvdcss_read() expects to be able to write \p i_blocks *
606
 *          #DVDCSS_BLOCK_SIZE bytes into \p p_buffer.
607
 */
608
LIBDVDCSS_EXPORT int dvdcss_read ( dvdcss_t dvdcss, void *p_buffer,
609
610
                                          int i_blocks,
                                          int i_flags )
Sam Hocevar's avatar
 
Sam Hocevar committed
611
612
613
{
    int i_ret, i_index;

614
    i_ret = dvdcss->pf_read( dvdcss, p_buffer, i_blocks );
Sam Hocevar's avatar
 
Sam Hocevar committed
615
616

    if( i_ret <= 0
617
         || !dvdcss->b_scrambled
Sam Hocevar's avatar
 
Sam Hocevar committed
618
619
620
621
622
         || !(i_flags & DVDCSS_READ_DECRYPT) )
    {
        return i_ret;
    }

623
    if( ! memcmp( dvdcss->css.p_title_key, "\0\0\0\0\0", 5 ) )
Sam Hocevar's avatar
 
Sam Hocevar committed
624
    {
625
        /* For what we believe is an unencrypted title,
Sam Hocevar's avatar
Sam Hocevar committed
626
         * check that there are no encrypted blocks */
Sam Hocevar's avatar
 
Sam Hocevar committed
627
628
        for( i_index = i_ret; i_index; i_index-- )
        {
629
            if( ((uint8_t*)p_buffer)[0x14] & 0x30 )
Sam Hocevar's avatar
 
Sam Hocevar committed
630
            {
631
                print_error( dvdcss, "no key but found encrypted block" );
Sam Hocevar's avatar
 
Sam Hocevar committed
632
633
                /* Only return the initial range of unscrambled blocks? */
                /* or fail completely? return 0; */
Sam Hocevar's avatar
Sam Hocevar committed
634
                break;
Sam Hocevar's avatar
 
Sam Hocevar committed
635
            }
636
            p_buffer = (uint8_t *)p_buffer + DVDCSS_BLOCK_SIZE;
Sam Hocevar's avatar
 
Sam Hocevar committed
637
638
        }
    }
639
    else
Sam Hocevar's avatar
 
Sam Hocevar committed
640
    {
641
642
        /* Decrypt the blocks we managed to read */
        for( i_index = i_ret; i_index; i_index-- )
Sam Hocevar's avatar
Sam Hocevar committed
643
        {
644
            dvdcss_unscramble( dvdcss->css.p_title_key, p_buffer );
Sam Hocevar's avatar
Sam Hocevar committed
645
            ((uint8_t*)p_buffer)[0x14] &= 0x8f;
646
            p_buffer = (uint8_t *)p_buffer + DVDCSS_BLOCK_SIZE;
Sam Hocevar's avatar
Sam Hocevar committed
647
        }
Sam Hocevar's avatar
 
Sam Hocevar committed
648
    }
649

Sam Hocevar's avatar
 
Sam Hocevar committed
650
651
652
    return i_ret;
}

653
/**
654
 * \brief Read data from the disc into multiple buffers and decrypt data if
655
656
 *        requested.
 *
657
 * \param dvdcss a \e libdvdcss instance
658
 * \param p_iovec a pointer to an array of iovec structures that will contain
659
660
661
662
 *        the data read from the disc
 * \param i_blocks the amount of blocks to read
 * \param i_flags #DVDCSS_NOFLAGS, optionally ORed with #DVDCSS_READ_DECRYPT
 * \return the amount of blocks read or a negative value in case an
663
664
 *         error happened.
 *
665
 * Read \p i_blocks logical blocks from the DVD and write them
666
667
668
669
670
671
672
673
 * to an array of iovec structures.
 *
 * You typically set \p i_flags to #DVDCSS_NOFLAGS when reading data from a
 * .IFO file on the DVD.
 *
 * If #DVDCSS_READ_DECRYPT is specified in \p i_flags, dvdcss_readv() will
 * automatically decrypt scrambled sectors. This flag is typically used when
 * reading data from a .VOB file on the DVD. It has no effect on unscrambled
674
 * discs or unscrambled sectors and can be safely used on those.
675
676
 *
 * \warning dvdcss_readv() expects to be able to write \p i_blocks *
677
 *          #DVDCSS_BLOCK_SIZE bytes into the buffers pointed by \p p_iovec.
678
679
680
 *          Moreover, all iov_len members of the iovec structures should be
 *          multiples of #DVDCSS_BLOCK_SIZE.
 */
681
LIBDVDCSS_EXPORT int dvdcss_readv ( dvdcss_t dvdcss, void *p_iovec,
682
683
                                           int i_blocks,
                                           int i_flags )
Sam Hocevar's avatar
 
Sam Hocevar committed
684
{
685
    struct iovec *_p_iovec = p_iovec;
Sam Hocevar's avatar
 
Sam Hocevar committed
686
687
688
689
    int i_ret, i_index;
    void *iov_base;
    size_t iov_len;

690
    i_ret = dvdcss->pf_readv( dvdcss, _p_iovec, i_blocks );
Sam Hocevar's avatar
 
Sam Hocevar committed
691
692

    if( i_ret <= 0
693
         || !dvdcss->b_scrambled
Sam Hocevar's avatar
 
Sam Hocevar committed
694
695
696
697
698
699
         || !(i_flags & DVDCSS_READ_DECRYPT) )
    {
        return i_ret;
    }

    /* Initialize loop for decryption */
700
701
    iov_base = _p_iovec->iov_base;
    iov_len = _p_iovec->iov_len;
Sam Hocevar's avatar
 
Sam Hocevar committed
702
703
704
705
706
707
708
709
710
711
712
713

    /* Decrypt the blocks we managed to read */
    for( i_index = i_ret; i_index; i_index-- )
    {
        /* Check that iov_len is a multiple of 2048 */
        if( iov_len & 0x7ff )
        {
            return -1;
        }

        while( iov_len == 0 )
        {
714
715
716
            _p_iovec++;
            iov_base = _p_iovec->iov_base;
            iov_len = _p_iovec->iov_len;
Sam Hocevar's avatar
 
Sam Hocevar committed
717
718
        }

719
        dvdcss_unscramble( dvdcss->css.p_title_key, iov_base );
720
        ((uint8_t*)iov_base)[0x14] &= 0x8f;
Sam Hocevar's avatar
 
Sam Hocevar committed
721

722
        iov_base = (uint8_t*)iov_base + DVDCSS_BLOCK_SIZE;
723
        iov_len -= DVDCSS_BLOCK_SIZE;
Sam Hocevar's avatar
 
Sam Hocevar committed
724
725
726
727
728
    }

    return i_ret;
}

729
/**
730
 * \brief Clean up library state and structures.
731
 *
732
 * \param dvdcss a \e libdvdcss instance
733
734
 * \return zero in case of success, a negative value otherwise.
 *
735
736
 * Close the DVD device and free all the memory allocated by \e libdvdcss.
 * On return, the #dvdcss_t is invalidated and may not be used again.
737
 */
738
LIBDVDCSS_EXPORT int dvdcss_close ( dvdcss_t dvdcss )
Sam Hocevar's avatar
 
Sam Hocevar committed
739
740
741
742
743
744
745
746
747
748
749
750
751
{
    dvd_title_t *p_title;
    int i_ret;

    /* Free our list of keys */
    p_title = dvdcss->p_titles;
    while( p_title )
    {
        dvd_title_t *p_tmptitle = p_title->p_next;
        free( p_title );
        p_title = p_tmptitle;
    }

752
    i_ret = dvdcss_close_device( dvdcss );
Sam Hocevar's avatar
 
Sam Hocevar committed
753
754
755
756
757
758

    if( i_ret < 0 )
    {
        return i_ret;
    }

759
    free( dvdcss->psz_device );
Sam Hocevar's avatar
 
Sam Hocevar committed
760
761
762
763
764
    free( dvdcss );

    return 0;
}

765
/**
766
 * \brief Detect whether or not a DVD is scrambled
767
768
769
770
771
772
773
774
 *
 * \param dvdcss a \e libdvdcss instance.
 * \return 1 if the DVD is scrambled, 0 otherwise.
 */
LIBDVDCSS_EXPORT int dvdcss_is_scrambled ( dvdcss_t dvdcss )
{
    return dvdcss->b_scrambled;
}