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+/* libdvdcss.c: DVD reading library.
+ *
+ * Authors: Stéphane Borel <stef@via.ecp.fr>
+ * Sam Hocevar <sam@zoy.org>
+ * Håkan Hjort <d95hjort@dtek.chalmers.se>
+ *
+ * Copyright (C) 1998-2008 VideoLAN
+ *
+ * libdvdcss is free software; you can redistribute it and/or modify
+ * 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.
+ *
+ * libdvdcss is distributed in the hope that it will be useful,
+ * 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.
+ *
+ * You should have received a copy of the GNU General Public License along
+ * with libdvdcss; if not, write to the Free Software Foundation, Inc.,
+ * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
+ */
+
+/**
+ * \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:
+ * \li portability: Currently supported platforms are GNU/Linux, FreeBSD,
+ * NetBSD, OpenBSD, Haiku, Mac OS X, Solaris, QNX, OS/2, and Windows
+ * 2000 or later.
+ * \li adaptability: Unlike most similar projects, libdvdcss does not require
+ * 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.
+ * \li simplicity: A DVD player can be built around the \e libdvdcss API using
+ * no more than 4 or 5 library calls.
+ *
+ * \e libdvdcss is free software, released under the GNU General Public License.
+ * 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
+ *
+ * Some environment variables can be used to change the behavior of
+ * \e libdvdcss without having to modify the program which uses it. These
+ * variables are:
+ *
+ * \li \b DVDCSS_VERBOSE: Sets the verbosity level.
+ * - \c 0 outputs no messages at all.
+ * - \c 1 outputs error messages to stderr.
+ * - \c 2 outputs error messages and debug messages to stderr.
+ *
+ * \li \b DVDCSS_METHOD: Sets the authentication and decryption method
+ * 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
+ * crypto attack to guess the title key. In rare cases this may fail
+ * because there is not enough encrypted data on the disc to perform
+ * a statistical attack, but on the other hand it is the only way to
+ * decrypt a DVD stored on a hard disc, or a DVD with the wrong region
+ * on an RPC2 drive.
+ *
+ * \li \b DVDCSS_RAW_DEVICE: Specify the raw device to use. Exact usage will
+ * 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).
+ *
+ * \li \b DVDCSS_CACHE: Specify a directory in which to cache title key
+ * 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
+ * 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.
+ */
+
+/*
+ * Preamble
+ */
+#include "config.h"
+
+#include <limits.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <sys/types.h>
+#include <sys/stat.h>
+#ifdef HAVE_SYS_PARAM_H
+# include <sys/param.h>
+#endif
+#ifdef HAVE_PWD_H
+# include <pwd.h>
+#endif
+#include <fcntl.h>
+#include <errno.h>
+
+#ifdef HAVE_UNISTD_H
+# include <unistd.h>
+#endif
+
+#ifdef _WIN32
+# include <windows.h>
+# include <shlobj.h>
+#endif
+
+#include "dvdcss/dvdcss.h"
+
+#include "common.h"
+#include "css.h"
+#include "libdvdcss.h"
+#include "ioctl.h"
+#include "device.h"
+
+#ifdef HAVE_BROKEN_MKDIR
+#include <direct.h>
+#define mkdir(a, b) _mkdir(a)
+#endif
+
+#define CACHE_TAG_NAME "CACHEDIR.TAG"
+
+#define STRING_KEY_SIZE (DVD_KEY_SIZE * 2)
+#define INTERESTING_SECTOR 16
+#define DISC_TITLE_OFFSET 40
+#define DISC_TITLE_LENGTH 32
+#define MANUFACTURING_DATE_OFFSET 813
+#define MANUFACTURING_DATE_LENGTH 16
+
+static int exists_or_mkdir( const char *path, int perm )
+{
+ /* mkdir() may return an error if making the directory would fail,
+ * even if the directory exists, so use stat() to test for existence
+ * before trying to make the directory. */
+ struct stat st;
+ if( stat(path, &st) )
+ return mkdir(path, perm);
+ return 0;
+}
+
+static dvdcss_t dvdcss_open_common ( const char *psz_target, void *p_stream,
+ dvdcss_stream_cb *p_stream_cb );
+static void set_verbosity( dvdcss_t dvdcss )
+{
+ const char *psz_verbose = getenv( "DVDCSS_VERBOSE" );
+
+ dvdcss->b_debug = 0;
+ dvdcss->b_errors = 0;
+
+ if( psz_verbose != NULL )
+ {
+ int i = atoi( psz_verbose );
+
+ if( i >= 2 )
+ dvdcss->b_debug = 1;
+ if( i >= 1 )
+ dvdcss->b_errors = 1;
+ }
+}
+
+static int set_access_method( dvdcss_t dvdcss )
+{
+ const char *psz_method = getenv( "DVDCSS_METHOD" );
+
+ if( !psz_method )
+ return 0;
+
+ 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
+ {
+ print_error( dvdcss, "unknown decryption method %s, please choose "
+ "from 'title', 'key' or 'disc'", psz_method );
+ return -1;
+ }
+ return 0;
+}
+
+static int set_cache_directory( dvdcss_t dvdcss )
+{
+ char *psz_cache = getenv( "DVDCSS_CACHE" );
+
+ if( psz_cache && !strcmp( psz_cache, "off" ) )
+ {
+ return -1;
+ }
+
+ if( psz_cache == NULL || psz_cache[0] == '\0' )
+ {
+#ifdef _WIN32
+ char psz_home[PATH_MAX];
+
+ /* Cache our keys in
+ * C:\Documents and Settings\$USER\Application Data\dvdcss\ */
+ if (SHGetFolderPathA (NULL, CSIDL_APPDATA | CSIDL_FLAG_CREATE,
+ NULL, SHGFP_TYPE_CURRENT, psz_home ) == S_OK)
+ {
+ snprintf( dvdcss->psz_cachefile, PATH_MAX, "%s\\dvdcss", psz_home );
+ dvdcss->psz_cachefile[PATH_MAX - 1] = '\0';
+ psz_cache = dvdcss->psz_cachefile;
+ }
+#else
+#ifdef __ANDROID__
+ /* $HOME is not writable on __ANDROID__ so we have to create a custom
+ * directory in userland */
+ char *psz_home = "/sdcard/Android/data/org.videolan.dvdcss";
+
+ int i_ret = exists_or_mkdir( psz_home, 0755 );
+ if( i_ret < 0 && errno != EEXIST )
+ {
+ print_error( dvdcss, "failed creating home directory" );
+ psz_home = NULL;
+ }
+#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 && p_pwd->pw_dir && p_pwd->pw_dir[ 0 ] )
+ {
+ psz_home = p_pwd->pw_dir;
+ }
+#endif /* HAVE_PWD_H */
+
+#endif /* __ANDROID__ */
+
+ if( psz_home == NULL )
+ {
+ psz_home = getenv( "HOME" );
+ }
+
+ /* Cache our keys in ${HOME}/.dvdcss/ */
+ if( psz_home && psz_home[ 0 ] )
+ {
+ int home_pos = 0;
+
+#ifdef __OS2__
+ if( *psz_home == '/' || *psz_home == '\\')
+ {
+ const char *psz_unixroot = getenv("UNIXROOT");
+
+ if( psz_unixroot &&
+ psz_unixroot[0] &&
+ psz_unixroot[1] == ':' &&
+ psz_unixroot[2] == '\0')
+ {
+ strcpy( dvdcss->psz_cachefile, psz_unixroot );
+ home_pos = 2;
+ }
+ }
+#endif /* __OS2__ */
+ snprintf( dvdcss->psz_cachefile + home_pos, PATH_MAX - home_pos,
+ "%s/.dvdcss", psz_home );
+ dvdcss->psz_cachefile[PATH_MAX - 1] = '\0';
+ psz_cache = dvdcss->psz_cachefile;
+ }
+#endif /* ! defined( _WIN32 ) */
+ }
+ else
+ {
+ strncpy( dvdcss->psz_cachefile, psz_cache, PATH_MAX );
+ dvdcss->psz_cachefile[PATH_MAX - 1] = '\0';
+ }
+
+ /* Check that there is enough space for the cache directory path and the
+ * block filename. The +1s are path separators. */
+ if( psz_cache && strlen( psz_cache ) + 1 + DISC_TITLE_LENGTH + 1 +
+ MANUFACTURING_DATE_LENGTH + 1 + STRING_KEY_SIZE + 1 +
+ sizeof(CACHE_TAG_NAME) > PATH_MAX )
+ {
+ print_error( dvdcss, "cache directory name is too long" );
+ return -1;
+ }
+ return 0;
+}
+
+static int init_cache_dir( dvdcss_t dvdcss )
+{
+ static const char psz_tag[] =
+ "Signature: 8a477f597d28d172789f06886806bc55\r\n"
+ "# 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";
+ char psz_tagfile[PATH_MAX];
+ int i_fd, i_ret;
+
+ i_ret = exists_or_mkdir( dvdcss->psz_cachefile, 0755 );
+ if( i_ret < 0 && errno != EEXIST )
+ {
+ print_error( dvdcss, "failed creating cache directory '%s'", dvdcss->psz_cachefile );
+ dvdcss->psz_cachefile[0] = '\0';
+ return -1;
+ }
+
+ i_ret = snprintf( psz_tagfile, PATH_MAX, "%s/" CACHE_TAG_NAME,
+ dvdcss->psz_cachefile );
+ if ( i_ret < 0 || i_ret >= PATH_MAX)
+ {
+ if ( i_ret < 0)
+ print_error( dvdcss, "failed to compose cache directory tag path");
+ else
+ print_error( dvdcss, "cache directory tag path too long: %s/" CACHE_TAG_NAME,
+ dvdcss->psz_cachefile );
+ dvdcss->psz_cachefile[0] = '\0';
+ return -1;
+ }
+
+ i_fd = open( psz_tagfile, O_RDWR|O_CREAT, 0644 );
+ if( i_fd >= 0 )
+ {
+ ssize_t len = strlen(psz_tag);
+ if( write( i_fd, psz_tag, len ) < len )
+ {
+ print_error( dvdcss,
+ "Error writing cache directory tag, continuing..\n" );
+ }
+ close( i_fd );
+ }
+ return 0;
+}
+
+static void create_cache_subdir( dvdcss_t dvdcss )
+{
+ uint8_t p_sector[DVDCSS_BLOCK_SIZE];
+ char psz_key[STRING_KEY_SIZE + 1];
+ char *psz_title;
+ uint8_t *psz_serial;
+ int i, i_ret;
+
+ /* 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 error;
+ }
+
+ i_ret = dvdcss->pf_read( dvdcss, p_sector, 1 );
+ if( i_ret != 1 )
+ {
+ goto error;
+ }
+
+ if( p_sector[0] == 0x00 && p_sector[1] == 0x00
+ && p_sector[2] == 0x01 && p_sector[3] == 0xba )
+ {
+ goto error;
+ }
+
+ /* 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, INTERESTING_SECTOR );
+ if( i_ret != INTERESTING_SECTOR )
+ {
+ goto error;
+ }
+
+ i_ret = dvdcss->pf_read( dvdcss, p_sector, 1 );
+ if( i_ret != 1 )
+ {
+ goto error;
+ }
+
+ /* Get the disc title */
+ psz_title = (char *)p_sector + DISC_TITLE_OFFSET;
+ psz_title[DISC_TITLE_LENGTH] = '\0';
+
+ for( i = 0; i < DISC_TITLE_LENGTH; i++ )
+ {
+ if( psz_title[i] <= ' ' )
+ {
+ psz_title[i] = '\0';
+ break;
+ }
+ else if( psz_title[i] == '/' || psz_title[i] == '\\' )
+ {
+ psz_title[i] = '-';
+ }
+ }
+
+ /* Get the date + serial */
+ psz_serial = p_sector + MANUFACTURING_DATE_OFFSET;
+ psz_serial[MANUFACTURING_DATE_LENGTH] = '\0';
+
+ /* Check that all characters are digits, otherwise convert. */
+ for( i = 0 ; i < MANUFACTURING_DATE_LENGTH ; i++ )
+ {
+ if( psz_serial[i] < '0' || psz_serial[i] > '9' )
+ {
+ char psz_tmp[MANUFACTURING_DATE_LENGTH + 1];
+ sprintf( psz_tmp,
+ "%.2x%.2x%.2x%.2x%.2x%.2x%.2x%.2x",
+ psz_serial[0], psz_serial[1], psz_serial[2],
+ psz_serial[3], psz_serial[4], psz_serial[5],
+ psz_serial[6], psz_serial[7] );
+ memcpy( psz_serial, psz_tmp, MANUFACTURING_DATE_LENGTH );
+ break;
+ }
+ }
+
+ /* Get disk key, since some discs have the same title, manufacturing
+ * date and serial number, but different keys. */
+ if( dvdcss->b_scrambled )
+ {
+ for( i = 0; i < DVD_KEY_SIZE; i++ )
+ {
+ sprintf( &psz_key[i * 2], "%.2x", dvdcss->css.p_disc_key[i] );
+ }
+ psz_key[STRING_KEY_SIZE] = '\0';
+ }
+ else
+ {
+ psz_key[0] = 0;
+ }
+
+ /* We have a disc name or ID, we can create the cache subdirectory. */
+ i = strlen( dvdcss->psz_cachefile );
+ i += sprintf( dvdcss->psz_cachefile + i, "/%s-%s-%s",
+ psz_title, psz_serial, psz_key );
+ i_ret = exists_or_mkdir( dvdcss->psz_cachefile, 0755 );
+ if( i_ret < 0 && errno != EEXIST )
+ {
+ print_error( dvdcss, "failed creating cache subdirectory" );
+ goto error;
+ }
+ i += sprintf( dvdcss->psz_cachefile + i, "/");
+
+ /* Pointer to the filename we will use. */
+ dvdcss->psz_block = dvdcss->psz_cachefile + i;
+
+ print_debug( dvdcss, "Content Scrambling System (CSS) key cache dir: %s",
+ dvdcss->psz_cachefile );
+ return;
+
+error:
+ dvdcss->psz_cachefile[0] = '\0';
+}
+
+static void init_cache( dvdcss_t dvdcss )
+{
+ /* Set CSS key cache directory. */
+ int i_ret = set_cache_directory( dvdcss );
+ if ( i_ret < 0 )
+ {
+ return;
+ }
+
+ /* If the cache is enabled, initialize the cache directory. */
+ i_ret = init_cache_dir( dvdcss );
+ if ( i_ret < 0 )
+ {
+ return;
+ }
+
+ /* If the cache is enabled, create a DVD-specific subdirectory. */
+ create_cache_subdir( dvdcss );
+}
+
+/**
+ * \brief Open a DVD device or directory and return a dvdcss instance.
+ *
+ * \param psz_target a string containing the target name, for instance
+ * "/dev/hdc" or "E:"
+ * \return a handle to a dvdcss instance or NULL on error.
+ *
+ * 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,
+ * and when possible, the disc key is retrieved.
+ */
+LIBDVDCSS_EXPORT dvdcss_t dvdcss_open ( const char *psz_target )
+{
+ return dvdcss_open_common( psz_target, NULL, NULL );
+}
+
+/**
+ * \brief Open a DVD device using dvdcss_stream_cb.
+ *
+ * \param p_stream a private handle used by p_stream_cb
+ * \param p_stream_cb a struct containing seek and read functions
+ * \return a handle to a dvdcss instance or NULL on error.
+ *
+ * \see dvdcss_open()
+ */
+LIBDVDCSS_EXPORT dvdcss_t dvdcss_open_stream ( void *p_stream,
+ dvdcss_stream_cb *p_stream_cb )
+{
+ return dvdcss_open_common( NULL, p_stream, p_stream_cb );
+}
+
+static dvdcss_t dvdcss_open_common ( const char *psz_target, void *p_stream,
+ dvdcss_stream_cb *p_stream_cb )
+{
+ int i_ret;
+
+ /* Allocate the library structure. */
+ dvdcss_t dvdcss = malloc( sizeof( *dvdcss ) );
+ if( dvdcss == NULL )
+ {
+ return NULL;
+ }
+
+ if( psz_target == NULL &&
+ ( p_stream == NULL || p_stream_cb == NULL ) )
+ {
+ dvdcss->psz_device = NULL;
+ goto error;
+ }
+
+ /* Initialize structure with default values. */
+ dvdcss->i_fd = -1;
+ dvdcss->i_pos = 0;
+ dvdcss->p_titles = NULL;
+ dvdcss->psz_device = psz_target ? strdup( psz_target ) : NULL;
+ dvdcss->psz_error = "no error";
+ dvdcss->i_method = DVDCSS_METHOD_KEY;
+ dvdcss->psz_cachefile[0] = '\0';
+
+ dvdcss->p_stream = p_stream;
+ dvdcss->p_stream_cb = p_stream_cb;
+
+ /* Set library verbosity from DVDCSS_VERBOSE environment variable. */
+ set_verbosity( dvdcss );
+
+ /* Set DVD access method from DVDCSS_METHOD environment variable. */
+ if( set_access_method( dvdcss ) < 0 )
+ {
+ goto error;
+ }
+
+ /* Open device. */
+ dvdcss_check_device( dvdcss );
+ i_ret = dvdcss_open_device( dvdcss );
+ if( i_ret < 0 )
+ {
+ goto error;
+ }
+
+ dvdcss->b_scrambled = 1; /* Assume the worst */
+ dvdcss->b_ioctls = dvdcss_use_ioctls( dvdcss );
+
+ if( dvdcss->b_ioctls )
+ {
+ i_ret = dvdcss_test( dvdcss );
+
+ if( i_ret == -3 )
+ {
+ print_debug( dvdcss, "scrambled disc on a region-free RPC-II "
+ "drive: possible failure, but continuing "
+ "anyway" );
+ }
+ else if( i_ret < 0 )
+ {
+ /* Disable the CSS ioctls and hope that it works? */
+ print_debug( dvdcss,
+ "could not check whether the disc was scrambled" );
+ dvdcss->b_ioctls = 0;
+ }
+ else
+ {
+ print_debug( dvdcss, i_ret ? "disc is scrambled"
+ : "disc is unscrambled" );
+ dvdcss->b_scrambled = i_ret;
+ }
+ }
+
+ memset( dvdcss->css.p_disc_key, 0, DVD_KEY_SIZE );
+ /* If disc is CSS protected and the ioctls work, authenticate the drive */
+ if( dvdcss->b_scrambled && dvdcss->b_ioctls )
+ {
+ i_ret = dvdcss_disckey( dvdcss );
+
+ if( i_ret < 0 )
+ {
+ print_debug( dvdcss, "could not get disc key" );
+ }
+ }
+
+ init_cache( dvdcss );
+
+ /* Seek to the beginning, just for safety. */
+ dvdcss->pf_seek( dvdcss, 0 );
+
+ return dvdcss;
+
+error:
+ free( dvdcss->psz_device );
+ free( dvdcss );
+ return NULL;
+}
+
+/**
+ * \brief Return a string containing the last error that occurred in the
+ * given \e libdvdcss instance.
+ *
+ * \param dvdcss a \e libdvdcss instance
+ * \return a NULL-terminated string containing the last error message.
+ *
+ * Return a string with the last error message produced by \e libdvdcss.
+ * Useful to conveniently format error messages in external applications.
+ */
+LIBDVDCSS_EXPORT const char * dvdcss_error ( const dvdcss_t dvdcss )
+{
+ return dvdcss->psz_error;
+}
+
+/**
+ * \brief Seek in the disc and change the current key if requested.
+ *
+ * \param dvdcss a \e libdvdcss instance
+ * \param i_blocks an absolute block offset to seek to
+ * \param i_flags #DVDCSS_NOFLAGS, optionally ORed with one of #DVDCSS_SEEK_KEY
+ * or #DVDCSS_SEEK_MPEG
+ * \return the new position in blocks or a negative value in case an error
+ * 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
+ * reasonable to do so (i.e., if the dvdcss method is not "title"), the current
+ * title key will be checked and a new one will be calculated if necessary.
+ * This flag is typically used when reading data from a .VOB file.
+ *
+ * If #DVDCSS_SEEK_KEY is specified, the title key will always be checked,
+ * even with the "title" method. This flag is typically used when seeking
+ * in a new title.
+ */
+LIBDVDCSS_EXPORT int dvdcss_seek ( dvdcss_t dvdcss, int i_blocks, int i_flags )
+{
+ /* title cracking method is too slow to be used at each seek */
+ if( ( ( i_flags & DVDCSS_SEEK_MPEG )
+ && ( dvdcss->i_method != DVDCSS_METHOD_TITLE ) )
+ || ( i_flags & DVDCSS_SEEK_KEY ) )
+ {
+ /* check the title key */
+ if( dvdcss_title( dvdcss, i_blocks ) )
+ {
+ return -1;
+ }
+ }
+
+ return dvdcss->pf_seek( dvdcss, i_blocks );
+}
+
+/**
+ * \brief Read from the disc and decrypt data if requested.
+ *
+ * \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
+ * error happened.
+ *
+ * Read \p i_blocks logical blocks from the DVD.
+ *
+ * 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
+ * discs or unscrambled sectors and can be safely used on those.
+ *
+ * \warning dvdcss_read() expects to be able to write \p i_blocks *
+ * #DVDCSS_BLOCK_SIZE bytes into \p p_buffer.
+ */
+LIBDVDCSS_EXPORT int dvdcss_read ( dvdcss_t dvdcss, void *p_buffer,
+ int i_blocks,
+ int i_flags )
+{
+ uint8_t *_p_buffer = p_buffer;
+ int i_ret, i_index;
+
+ i_ret = dvdcss->pf_read( dvdcss, _p_buffer, i_blocks );
+
+ if( i_ret <= 0
+ || !dvdcss->b_scrambled
+ || !(i_flags & DVDCSS_READ_DECRYPT) )
+ {
+ return i_ret;
+ }
+
+ if( ! memcmp( dvdcss->css.p_title_key, "\0\0\0\0\0", 5 ) )
+ {
+ /* For what we believe is an unencrypted title,
+ * check that there are no encrypted blocks */
+ for( i_index = i_ret; i_index; i_index-- )
+ {
+ if( _p_buffer[0x14] & 0x30 )
+ {
+ print_error( dvdcss, "no key but found encrypted block" );
+ /* Only return the initial range of unscrambled blocks? */
+ /* or fail completely? return 0; */
+ break;
+ }
+ _p_buffer = _p_buffer + DVDCSS_BLOCK_SIZE;
+ }
+ }
+ else
+ {
+ /* Decrypt the blocks we managed to read */
+ for( i_index = i_ret; i_index; i_index-- )
+ {
+ dvdcss_unscramble( dvdcss->css.p_title_key, _p_buffer );
+ _p_buffer[0x14] &= 0x8f;
+ _p_buffer = _p_buffer + DVDCSS_BLOCK_SIZE;
+ }
+ }
+
+ return i_ret;
+}
+
+/**
+ * \brief Read data from the disc into multiple buffers and decrypt data if
+ * requested.
+ *
+ * \param dvdcss a \e libdvdcss instance
+ * \param p_iovec a pointer to an array of iovec structures 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
+ * error happened.
+ *
+ * Read \p i_blocks logical blocks from the DVD and write them
+ * 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
+ * discs or unscrambled sectors and can be safely used on those.
+ *
+ * \warning dvdcss_readv() expects to be able to write \p i_blocks *
+ * #DVDCSS_BLOCK_SIZE bytes into the buffers pointed by \p p_iovec.
+ * Moreover, all iov_len members of the iovec structures should be
+ * multiples of #DVDCSS_BLOCK_SIZE.
+ */
+LIBDVDCSS_EXPORT int dvdcss_readv ( dvdcss_t dvdcss, void *p_iovec,
+ int i_blocks,
+ int i_flags )
+{
+ struct iovec *_p_iovec = p_iovec;
+ int i_ret, i_index;
+ void *iov_base;
+ size_t iov_len;
+
+ i_ret = dvdcss->pf_readv( dvdcss, _p_iovec, i_blocks );
+
+ if( i_ret <= 0
+ || !dvdcss->b_scrambled
+ || !(i_flags & DVDCSS_READ_DECRYPT) )
+ {
+ return i_ret;
+ }
+
+ /* Initialize loop for decryption */
+ iov_base = _p_iovec->iov_base;
+ iov_len = _p_iovec->iov_len;
+
+ /* 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 )
+ {
+ _p_iovec++;
+ iov_base = _p_iovec->iov_base;
+ iov_len = _p_iovec->iov_len;
+ }
+
+ dvdcss_unscramble( dvdcss->css.p_title_key, iov_base );
+ ((uint8_t*)iov_base)[0x14] &= 0x8f;
+
+ iov_base = (uint8_t*)iov_base + DVDCSS_BLOCK_SIZE;
+ iov_len -= DVDCSS_BLOCK_SIZE;
+ }
+
+ return i_ret;
+}
+
+/**
+ * \brief Clean up library state and structures.
+ *
+ * \param dvdcss a \e libdvdcss instance
+ * \return zero in case of success, a negative value otherwise.
+ *
+ * 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.
+ */
+LIBDVDCSS_EXPORT int dvdcss_close ( dvdcss_t dvdcss )
+{
+ struct dvd_title *p_title;
+ int i_ret;
+
+ /* Free our list of keys */
+ p_title = dvdcss->p_titles;
+ while( p_title )
+ {
+ struct dvd_title *p_tmptitle = p_title->p_next;
+ free( p_title );
+ p_title = p_tmptitle;
+ }
+
+ i_ret = dvdcss_close_device( dvdcss );
+
+ free( dvdcss->psz_device );
+ free( dvdcss );
+
+ return i_ret;
+}
+
+/**
+ * \brief Detect whether or not a DVD is scrambled
+ *
+ * \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;
+}