886 lines
27 KiB
C
886 lines
27 KiB
C
/* libdvdcss.c: DVD reading library.
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*
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* Authors: Stéphane Borel <stef@via.ecp.fr>
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* Sam Hocevar <sam@zoy.org>
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* Håkan Hjort <d95hjort@dtek.chalmers.se>
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*
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* Copyright (C) 1998-2008 VideoLAN
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*
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* libdvdcss is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation; either version 2 of the License, or
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* (at your option) any later version.
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*
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* libdvdcss is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License along
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* with libdvdcss; if not, write to the Free Software Foundation, Inc.,
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* 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
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*/
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/**
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* \mainpage libdvdcss developer documentation
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*
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* \section intro Introduction
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*
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* \e libdvdcss is a simple library designed for accessing DVDs like a block
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* device without having to bother about the decryption. The important features
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* are:
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* \li portability: Currently supported platforms are GNU/Linux, FreeBSD,
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* NetBSD, OpenBSD, Haiku, Mac OS X, Solaris, QNX, OS/2, and Windows
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* 2000 or later.
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* \li adaptability: Unlike most similar projects, libdvdcss does not require
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* the region of your drive to be set and will try its best to read from
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* the disc even in the case of a region mismatch.
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* \li simplicity: A DVD player can be built around the \e libdvdcss API using
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* no more than 4 or 5 library calls.
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*
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* \e libdvdcss is free software, released under the GNU General Public License.
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* This ensures that \e libdvdcss remains free and used only with free
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* software.
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*
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* \section api The libdvdcss API
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*
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* The complete \e libdvdcss programming interface is documented in the
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* dvdcss.h file.
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*
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* \section env Environment variables
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*
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* Some environment variables can be used to change the behavior of
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* \e libdvdcss without having to modify the program which uses it. These
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* variables are:
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*
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* \li \b DVDCSS_VERBOSE: Sets the verbosity level.
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* - \c 0 outputs no messages at all.
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* - \c 1 outputs error messages to stderr.
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* - \c 2 outputs error messages and debug messages to stderr.
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*
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* \li \b DVDCSS_METHOD: Sets the authentication and decryption method
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* that \e libdvdcss will use to read scrambled discs. Can be one
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* of \c title, \c key or \c disc.
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* - \c key is the default method. \e libdvdcss will use a set of
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* calculated player keys to try and get the disc key. This can fail
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* if the drive does not recognize any of the player keys.
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* - \c disc is a fallback method when \c key has failed. Instead of
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* using player keys, \e libdvdcss will crack the disc key using
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* a brute force algorithm. This process is CPU intensive and requires
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* 64 MB of memory to store temporary data.
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* - \c title is the fallback when all other methods have failed. It does
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* not rely on a key exchange with the DVD drive, but rather uses a
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* crypto attack to guess the title key. In rare cases this may fail
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* because there is not enough encrypted data on the disc to perform
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* a statistical attack, but on the other hand it is the only way to
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* decrypt a DVD stored on a hard disc, or a DVD with the wrong region
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* on an RPC2 drive.
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*
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* \li \b DVDCSS_RAW_DEVICE: Specify the raw device to use. Exact usage will
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* depend on your operating system, the Linux utility to set up raw devices
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* is \c raw(8) for instance. Please note that on most operating systems,
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* using a raw device requires highly aligned buffers: Linux requires a
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* 2048 bytes alignment (which is the size of a DVD sector).
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*
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* \li \b DVDCSS_CACHE: Specify a directory in which to cache title key
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* values. This will speed up descrambling of DVDs which are in the
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* cache. The DVDCSS_CACHE directory is created if it does not exist,
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* and a subdirectory is created named after the DVD's title or
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* manufacturing date. If DVDCSS_CACHE is not set or is empty, \e libdvdcss
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* will use the default value which is "${HOME}/.dvdcss/" under Unix and
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* "C:\Documents and Settings\$USER\Application Data\dvdcss\" under Win32.
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* The special value "off" disables caching.
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*/
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/*
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* Preamble
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*/
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#include "config.h"
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#include <limits.h>
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#include <stdio.h>
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#include <stdlib.h>
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#include <string.h>
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#include <sys/types.h>
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#include <sys/stat.h>
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#ifdef HAVE_SYS_PARAM_H
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# include <sys/param.h>
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#endif
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#ifdef HAVE_PWD_H
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# include <pwd.h>
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#endif
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#include <fcntl.h>
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#include <errno.h>
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#ifdef HAVE_UNISTD_H
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# include <unistd.h>
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#endif
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#ifdef _WIN32
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# include <windows.h>
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# include <shlobj.h>
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#endif
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#include "dvdcss/dvdcss.h"
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#include "common.h"
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#include "css.h"
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#include "libdvdcss.h"
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#include "ioctl.h"
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#include "device.h"
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#ifdef HAVE_BROKEN_MKDIR
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#include <direct.h>
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#define mkdir(a, b) _mkdir(a)
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#endif
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#define CACHE_TAG_NAME "CACHEDIR.TAG"
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#define STRING_KEY_SIZE (DVD_KEY_SIZE * 2)
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#define INTERESTING_SECTOR 16
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#define DISC_TITLE_OFFSET 40
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#define DISC_TITLE_LENGTH 32
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#define MANUFACTURING_DATE_OFFSET 813
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#define MANUFACTURING_DATE_LENGTH 16
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static int exists_or_mkdir( const char *path, int perm )
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{
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/* mkdir() may return an error if making the directory would fail,
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* even if the directory exists, so use stat() to test for existence
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* before trying to make the directory. */
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struct stat st;
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if( stat(path, &st) )
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return mkdir(path, perm);
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return 0;
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}
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static dvdcss_t dvdcss_open_common ( const char *psz_target, void *p_stream,
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dvdcss_stream_cb *p_stream_cb );
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static void set_verbosity( dvdcss_t dvdcss )
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{
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const char *psz_verbose = getenv( "DVDCSS_VERBOSE" );
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dvdcss->b_debug = 0;
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dvdcss->b_errors = 0;
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if( psz_verbose != NULL )
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{
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int i = atoi( psz_verbose );
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if( i >= 2 )
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dvdcss->b_debug = 1;
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if( i >= 1 )
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dvdcss->b_errors = 1;
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}
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}
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static int set_access_method( dvdcss_t dvdcss )
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{
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const char *psz_method = getenv( "DVDCSS_METHOD" );
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if( !psz_method )
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return 0;
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if( !strncmp( psz_method, "key", 4 ) )
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{
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dvdcss->i_method = DVDCSS_METHOD_KEY;
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}
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else if( !strncmp( psz_method, "disc", 5 ) )
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{
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dvdcss->i_method = DVDCSS_METHOD_DISC;
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}
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else if( !strncmp( psz_method, "title", 5 ) )
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{
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dvdcss->i_method = DVDCSS_METHOD_TITLE;
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}
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else
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{
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print_error( dvdcss, "unknown decryption method %s, please choose "
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"from 'title', 'key' or 'disc'", psz_method );
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return -1;
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}
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return 0;
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}
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static int set_cache_directory( dvdcss_t dvdcss )
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{
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char *psz_cache = getenv( "DVDCSS_CACHE" );
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if( psz_cache && !strcmp( psz_cache, "off" ) )
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{
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return -1;
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}
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if( psz_cache == NULL || psz_cache[0] == '\0' )
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{
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#ifdef _WIN32
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char psz_home[PATH_MAX];
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/* Cache our keys in
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* C:\Documents and Settings\$USER\Application Data\dvdcss\ */
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if (SHGetFolderPathA (NULL, CSIDL_APPDATA | CSIDL_FLAG_CREATE,
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NULL, SHGFP_TYPE_CURRENT, psz_home ) == S_OK)
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{
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snprintf( dvdcss->psz_cachefile, PATH_MAX, "%s\\dvdcss", psz_home );
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dvdcss->psz_cachefile[PATH_MAX - 1] = '\0';
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psz_cache = dvdcss->psz_cachefile;
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}
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#else
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#ifdef __ANDROID__
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/* $HOME is not writable on __ANDROID__ so we have to create a custom
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* directory in userland */
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char *psz_home = "/sdcard/Android/data/org.videolan.dvdcss";
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int i_ret = exists_or_mkdir( psz_home, 0755 );
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if( i_ret < 0 && errno != EEXIST )
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{
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print_error( dvdcss, "failed creating home directory" );
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psz_home = NULL;
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}
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#else
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char *psz_home = NULL;
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#ifdef HAVE_PWD_H
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struct passwd *p_pwd;
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/* Try looking in password file for home dir. */
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p_pwd = getpwuid(getuid());
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if( p_pwd && p_pwd->pw_dir && p_pwd->pw_dir[ 0 ] )
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{
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psz_home = p_pwd->pw_dir;
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}
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#endif /* HAVE_PWD_H */
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#endif /* __ANDROID__ */
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if( psz_home == NULL )
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{
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psz_home = getenv( "HOME" );
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}
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/* Cache our keys in ${HOME}/.dvdcss/ */
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if( psz_home && psz_home[ 0 ] )
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{
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int home_pos = 0;
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#ifdef __OS2__
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if( *psz_home == '/' || *psz_home == '\\')
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{
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const char *psz_unixroot = getenv("UNIXROOT");
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if( psz_unixroot &&
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psz_unixroot[0] &&
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psz_unixroot[1] == ':' &&
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psz_unixroot[2] == '\0')
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{
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strcpy( dvdcss->psz_cachefile, psz_unixroot );
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home_pos = 2;
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}
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}
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#endif /* __OS2__ */
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snprintf( dvdcss->psz_cachefile + home_pos, PATH_MAX - home_pos,
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"%s/.dvdcss", psz_home );
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dvdcss->psz_cachefile[PATH_MAX - 1] = '\0';
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psz_cache = dvdcss->psz_cachefile;
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}
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#endif /* ! defined( _WIN32 ) */
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}
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else
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{
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strncpy( dvdcss->psz_cachefile, psz_cache, PATH_MAX );
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dvdcss->psz_cachefile[PATH_MAX - 1] = '\0';
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}
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/* Check that there is enough space for the cache directory path and the
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* block filename. The +1s are path separators. */
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if( psz_cache && strlen( psz_cache ) + 1 + DISC_TITLE_LENGTH + 1 +
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MANUFACTURING_DATE_LENGTH + 1 + STRING_KEY_SIZE + 1 +
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sizeof(CACHE_TAG_NAME) > PATH_MAX )
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{
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print_error( dvdcss, "cache directory name is too long" );
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return -1;
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}
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return 0;
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}
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static int init_cache_dir( dvdcss_t dvdcss )
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{
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static const char psz_tag[] =
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"Signature: 8a477f597d28d172789f06886806bc55\r\n"
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"# This file is a cache directory tag created by libdvdcss.\r\n"
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"# For information about cache directory tags, see:\r\n"
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"# http://www.brynosaurus.com/cachedir/\r\n";
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char psz_tagfile[PATH_MAX];
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int i_fd, i_ret;
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i_ret = exists_or_mkdir( dvdcss->psz_cachefile, 0755 );
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if( i_ret < 0 && errno != EEXIST )
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{
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print_error( dvdcss, "failed creating cache directory '%s'", dvdcss->psz_cachefile );
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dvdcss->psz_cachefile[0] = '\0';
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return -1;
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}
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i_ret = snprintf( psz_tagfile, PATH_MAX, "%s/" CACHE_TAG_NAME,
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dvdcss->psz_cachefile );
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if ( i_ret < 0 || i_ret >= PATH_MAX)
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{
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if ( i_ret < 0)
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print_error( dvdcss, "failed to compose cache directory tag path");
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else
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print_error( dvdcss, "cache directory tag path too long: %s/" CACHE_TAG_NAME,
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dvdcss->psz_cachefile );
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dvdcss->psz_cachefile[0] = '\0';
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return -1;
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}
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i_fd = open( psz_tagfile, O_RDWR|O_CREAT, 0644 );
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if( i_fd >= 0 )
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{
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ssize_t len = strlen(psz_tag);
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if( write( i_fd, psz_tag, len ) < len )
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{
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print_error( dvdcss,
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"Error writing cache directory tag, continuing..\n" );
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}
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close( i_fd );
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}
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return 0;
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}
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static void create_cache_subdir( dvdcss_t dvdcss )
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{
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uint8_t p_sector[DVDCSS_BLOCK_SIZE];
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char psz_key[STRING_KEY_SIZE + 1];
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char *psz_title;
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uint8_t *psz_serial;
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int i, i_ret;
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/* We read sector 0. If it starts with 0x000001ba (BE), we are
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* reading a VOB file, and we should not cache anything. */
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i_ret = dvdcss->pf_seek( dvdcss, 0 );
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if( i_ret != 0 )
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{
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goto error;
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}
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i_ret = dvdcss->pf_read( dvdcss, p_sector, 1 );
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if( i_ret != 1 )
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{
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goto error;
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}
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if( p_sector[0] == 0x00 && p_sector[1] == 0x00
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&& p_sector[2] == 0x01 && p_sector[3] == 0xba )
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{
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goto error;
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}
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/* The data we are looking for is at sector 16 (32768 bytes):
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* - offset 40: disc title (32 uppercase chars)
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* - offset 813: manufacturing date + serial no (16 digits) */
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i_ret = dvdcss->pf_seek( dvdcss, INTERESTING_SECTOR );
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if( i_ret != INTERESTING_SECTOR )
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{
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goto error;
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}
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i_ret = dvdcss->pf_read( dvdcss, p_sector, 1 );
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if( i_ret != 1 )
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{
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goto error;
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}
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/* Get the disc title */
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psz_title = (char *)p_sector + DISC_TITLE_OFFSET;
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psz_title[DISC_TITLE_LENGTH] = '\0';
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for( i = 0; i < DISC_TITLE_LENGTH; i++ )
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{
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if( psz_title[i] <= ' ' )
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{
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psz_title[i] = '\0';
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break;
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}
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else if( psz_title[i] == '/' || psz_title[i] == '\\' )
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{
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psz_title[i] = '-';
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}
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}
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/* Get the date + serial */
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psz_serial = p_sector + MANUFACTURING_DATE_OFFSET;
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psz_serial[MANUFACTURING_DATE_LENGTH] = '\0';
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/* Check that all characters are digits, otherwise convert. */
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for( i = 0 ; i < MANUFACTURING_DATE_LENGTH ; i++ )
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{
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if( psz_serial[i] < '0' || psz_serial[i] > '9' )
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{
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char psz_tmp[MANUFACTURING_DATE_LENGTH + 1];
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sprintf( psz_tmp,
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"%.2x%.2x%.2x%.2x%.2x%.2x%.2x%.2x",
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psz_serial[0], psz_serial[1], psz_serial[2],
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psz_serial[3], psz_serial[4], psz_serial[5],
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psz_serial[6], psz_serial[7] );
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memcpy( psz_serial, psz_tmp, MANUFACTURING_DATE_LENGTH );
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break;
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}
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}
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/* Get disk key, since some discs have the same title, manufacturing
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* date and serial number, but different keys. */
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if( dvdcss->b_scrambled )
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{
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for( i = 0; i < DVD_KEY_SIZE; i++ )
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{
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sprintf( &psz_key[i * 2], "%.2x", dvdcss->css.p_disc_key[i] );
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}
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psz_key[STRING_KEY_SIZE] = '\0';
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}
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else
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{
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psz_key[0] = 0;
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}
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/* We have a disc name or ID, we can create the cache subdirectory. */
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i = strlen( dvdcss->psz_cachefile );
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i += sprintf( dvdcss->psz_cachefile + i, "/%s-%s-%s",
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psz_title, psz_serial, psz_key );
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i_ret = exists_or_mkdir( dvdcss->psz_cachefile, 0755 );
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if( i_ret < 0 && errno != EEXIST )
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{
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print_error( dvdcss, "failed creating cache subdirectory" );
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goto error;
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}
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i += sprintf( dvdcss->psz_cachefile + i, "/");
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/* Pointer to the filename we will use. */
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dvdcss->psz_block = dvdcss->psz_cachefile + i;
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print_debug( dvdcss, "Content Scrambling System (CSS) key cache dir: %s",
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dvdcss->psz_cachefile );
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return;
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error:
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dvdcss->psz_cachefile[0] = '\0';
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}
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static void init_cache( dvdcss_t dvdcss )
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{
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/* Set CSS key cache directory. */
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int i_ret = set_cache_directory( dvdcss );
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if ( i_ret < 0 )
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{
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return;
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}
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/* If the cache is enabled, initialize the cache directory. */
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i_ret = init_cache_dir( dvdcss );
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if ( i_ret < 0 )
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{
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return;
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}
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/* If the cache is enabled, create a DVD-specific subdirectory. */
|
|
create_cache_subdir( dvdcss );
|
|
}
|
|
int dvdcss_was_error_common(dvdcss_t drive) {
|
|
if (drive->b_errors)
|
|
{
|
|
drive->b_errors = FALSE;
|
|
return TRUE;
|
|
}
|
|
return FALSE;
|
|
}
|
|
|
|
int dvdcss_get_fd_common(dvdcss_t drive) {
|
|
return drive->i_fd;
|
|
}
|
|
|
|
LIBDVDCSS_EXPORT int dvdcss_was_error(dvdcss_t drive)
|
|
{
|
|
return dvdcss_was_error_common(drive);
|
|
}
|
|
|
|
LIBDVDCSS_EXPORT int dvdcss_get_raw_fd(dvdcss_t drive)
|
|
{
|
|
return dvdcss_get_fd_common(drive);
|
|
}
|
|
|
|
/**
|
|
* \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;
|
|
}
|