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• Revision 34710 : Amélioration de la fonction d’installation ... très chouette en SPIP 2.1 ...

  24 janvier 2010, par kent1@… — Log

  Amélioration de la fonction d’installation ... très chouette en SPIP 2.1 (bis ...)

• Reverse Engineering Italian Literature

  1er juillet 2014, par Multimedia Mike — Reverse Engineering

  Some time ago, Diego “Flameeyes” Pettenò tried his hand at reverse engineering a set of really old CD-ROMs containing even older Italian literature. The goal of this RE endeavor would be to extract the useful literature along with any structural metadata (chapters, etc.) and convert it to a more open format suitable for publication at, e.g., Project Gutenberg or Archive.org.

  Unfortunately, the structure of the data thwarted the more simplistic analysis attempts (like inspecting for blocks of textual data). This will require deeper RE techniques. Further frustrating the effort, however, is the fact that the binaries that implement the reading program are written for the now-archaic Windows 3.1 operating system.

  In pursuit of this RE goal, I recently thought of a way to glean more intelligence using DOSBox.

  Prior Work
  There are 6 discs in the full set (distributed along with 6 sequential issues of a print magazine named L’Espresso). Analysis of the contents of the various discs reveals that many of the files are the same on each disc. It was straightforward to identify the set of files which are unique on each disc. This set of files all end with the extension “LZn”, where n = 1..6 depending on the disc number. Further, the root directory of each disc has a file indicating the sequence number (1..6) of the CD. Obviously, these are the interesting targets.

  The LZ file extensions stand out to an individual skilled in the art of compression– could it be a variation of the venerable LZ compression ? That’s actually unlikely because LZ — also seen as LIZ — stands for Letteratura Italiana Zanichelli (Zanichelli’s Italian Literature).

  The Unix ‘file’ command was of limited utility, unable to plausibly identify any of the files.

  Progress was stalled.

  Saying Hello To An Old Frenemy
  I have been showing this screenshot to younger coworkers to see if any of them recognize it :

  
  
  

  Not a single one has seen it before. Senior computer citizen status : Confirmed.

  I recently watched an Ancient DOS Games video about Windows 3.1 games. This episode showed Windows 3.1 running under DOSBox. I had heard this was possible but that it took a little work to get running. I had a hunch that someone else had probably already done the hard stuff so I took to the BitTorrent networks and quickly found a download that had the goods ready to go– a directory of Windows 3.1 files that just had to be dropped into a DOSBox directory and they would be ready to run.

  Aside : Running OS software procured from a BitTorrent network ? Isn’t that an insane security nightmare ? I’m not too worried since it effectively runs under a sandboxed virtual machine, courtesy of DOSBox. I suppose there’s the risk of trojan’d OS software infecting binaries that eventually leave the sandbox.

  Using DOSBox Like ‘strace’
  strace is a tool available on some Unix systems, including Linux, which is able to monitor the system calls that a program makes. In reverse engineering contexts, it can be useful to monitor an opaque, binary program to see the names of the files it opens and how many bytes it reads, and from which locations. I have written examples of this before (wow, almost 10 years ago to the day ; now I feel old for the second time in this post).

  Here’s the pitch : Make DOSBox perform as strace in order to serve as a platform for reverse engineering Windows 3.1 applications. I formed a mental model about how DOSBox operates — abstracted file system classes with methods for opening and reading files — and then jumped into the source code. Sure enough, the code was exactly as I suspected and a few strategic print statements gave me the data I was looking for.

  Eventually, I even took to running DOSBox under the GNU Debugger (GDB). This hasn’t proven especially useful yet, but it has led to an absurd level of nesting :

  
  
  

  The target application runs under Windows 3.1, which is running under DOSBox, which is running under GDB. This led to a crazy situation in which DOSBox had the mouse focus when a GDB breakpoint was triggered. At this point, DOSBox had all desktop input focus and couldn’t surrender it because it wasn’t running. I had no way to interact with the Linux desktop and had to reboot the computer. The next time, I took care to only use the keyboard to navigate the application and trigger the breakpoint and not allow DOSBox to consume the mouse focus.

  New Intelligence
  
  By instrumenting the local file class (virtual HD files) and the ISO file class (CD-ROM files), I was able to watch which programs and dynamic libraries are loaded and which data files the code cares about. I was able to narrow down the fact that the most interesting programs are called LEGGENDO.EXE (‘reading’) and LEGGENDA.EXE (‘legend’ ; this has been a great Italian lesson as well as RE puzzle). The first calls the latter, which displays this view of the data we are trying to get at :

  
  
  

  When first run, the program takes an interest in a file called DBBIBLIO (‘database library’, I suspect) :

  === Read(’LIZ98\DBBIBLIO.LZ1’) : req 337 bytes ; read 337 bytes from pos 0x0
  === Read(’LIZ98\DBBIBLIO.LZ1’) : req 337 bytes ; read 337 bytes from pos 0x151
  === Read(’LIZ98\DBBIBLIO.LZ1’) : req 337 bytes ; read 337 bytes from pos 0x2A2
  [...]
  

  While we were unable to sort out all of the data files in our cursory investigation, a few things were obvious. The structure of this file looked to contain 336-byte records. Turns out I was off by 1– the records are actually 337 bytes each. The count of records read from disc is equal to the number of items shown in the UI.

  Next, the program is interested in a few more files :

  *** isoFile() : ’DEPOSITO\BLOKCTC.LZ1’, offset 0x27D6000, 2911488 bytes large
  === Read(’DEPOSITO\BLOKCTC.LZ1’) : req 96 bytes ; read 96 bytes from pos 0x0
  *** isoFile() : ’DEPOSITO\BLOKCTX0.LZ1’, offset 0x2A9D000, 17152 bytes large
  === Read(’DEPOSITO\BLOKCTX0.LZ1’) : req 128 bytes ; read 128 bytes from pos 0x0
  === Seek(’DEPOSITO\BLOKCTX0.LZ1’) : seek 384 (0x180) bytes, type 0
  === Read(’DEPOSITO\BLOKCTX0.LZ1’) : req 256 bytes ; read 256 bytes from pos 0x180
  === Seek(’DEPOSITO\BLOKCTC.LZ1’) : seek 1152 (0x480) bytes, type 0
  === Read(’DEPOSITO\BLOKCTC.LZ1’) : req 32 bytes ; read 32 bytes from pos 0x480
  === Read(’DEPOSITO\BLOKCTC.LZ1’) : req 1504 bytes ; read 1504 bytes from pos 0x4A0
  [...]

  Eventually, it becomes obvious that BLOKCTC has the juicy meat. There are 32-byte records followed by variable-length encoded text sections. Since there is no text to be found in these files, the text is either compressed, encrypted, or both. Some rough counting (the program seems to disable copy/paste, which thwarts more precise counting), indicates that the text size is larger than the data chunks being read from disc, so compression seems likely. Encryption isn’t out of the question (especially since the program deems it necessary to disable copy and pasting of this public domain literary data), and if it’s in use, that means the key is being read from one of these files.

  Blocked On Disassembly
  So I’m a bit blocked right now. I know exactly where the data lives, but it’s clear that I need to reverse engineer some binary code. The big problem is that I have no idea how to disassemble Windows 3.1 binaries. These are NE-type executable files. Disassemblers abound for MZ files (MS-DOS executables) and PE files (executables for Windows 95 and beyond). NE files get no respect. It’s difficult (but not impossible) to even find data about the format anymore, and details are incomplete. It should be noted, however, the DOSBox-as-strace method described here lends insight into how Windows 3.1 processes NE-type EXEs. You can’t get any more authoritative than that.

  So far, I have tried the freeware version of IDA Pro. Unfortunately, I haven’t been able to get the program to work on my Windows machine for a long time. Even if I could, I can’t find any evidence that it actually supports NE files (the free version specifically mentions MZ and PE, but does not mention NE or LE).

  I found an old copy of Borland’s beloved Turbo Assembler and Debugger package. It has Turbo Debugger for Windows, both regular and 32-bit versions. Unfortunately, the normal version just hangs Windows 3.1 in DOSBox. The 32-bit Turbo Debugger loads just fine but can’t load the NE file.

  I’ve also wondered if DOSBox contains any advanced features for trapping program execution and disassembling. I haven’t looked too deeply into this yet.

  Future Work
  NE files seem to be the executable format that time forgot. I have a crazy brainstorm about repacking NE files as MZ executables so that they could be taken apart with an MZ disassembler. But this will take some experimenting.

  If anyone else has any ideas about ripping open these binaries, I would appreciate hearing them.

  And I guess I shouldn’t be too surprised to learn that all the literature in this corpus is already freely available and easily downloadable anyway. But you shouldn’t be too surprised if that doesn’t discourage me from trying to crack the format that’s keeping this particular copy of the data locked up.

• How do i properly setup ffmpeg and fix this "Permission Denied" error im getting ?

  8 décembre 2020, par ExaNori

  Error im getting
C:/Users/Motzumoto/Desktop/AGB/ffmpeg/bin: Permission denied

  


  I already have ffmpeg installed to path on my windows 10 machine, but that didnt fix it, so i just tried to put ffmpeg in my bots directory, that didnt do it either.
Heres my music code if anyone can help
It uses a mixture of youtube-dl and ffmpeg
If there are also any errors that would stop this from working at all it'd be nice if you could show me them, im quite tired of this as of now and im honestly just about to scrap this idea and forget about it

  


  I've tried linking the path to the ffmpeg.exe, that still didnt work, i got the same error, i have no idea what to do

  


  import asyncio
import logging
import math
from urllib import request

import discord
from discord.ext import commands
import youtube_dl
from utils.guilds import Guilds
import ffmpeg
from asyncio import run_coroutine_threadsafe as coroutine

DOWNLOAD_PATH = "audio" # download path of the file
STREAM_INDICATOR_PREFIX = "${STREAM}:"




# options
ytdl_options = {
    "quiet": True,
    "forceipv4": True,
    "noplaylist": True,
    "no_warnings": True,
    "ignoreerrors": True,
    "nooverwrites": True,
    "restrictfilenames": True,
    "nocheckcertificate": True,
    "default_search": "auto",
    "format": "bestaudio/best",
}
ffmpeg_options = {
    "options": "-vn" # indicates that we have disabled video recording in the output file
}

ytdl = youtube_dl.YoutubeDL(ytdl_options) # youtube_dl object

# checks functions
def is_connected(ctx):
    """Check if the bot is connected to a voice channel."""
    
    if ctx.voice_client:
        return True
    
    return False
def is_same_channel(ctx):
    """Check if the bot and the user is in the same channel."""
    
    # try to get their voice channel id if there's any
    try:
        bot_channel_id = ctx.voice_client.channel.id
        user_channel_id = ctx.author.voice.channel.id
    # if one of them is not connected to a voice channel then they're not together
    except AttributeError:
        return False
    
    # check if their voice channel id is the same
    if bot_channel_id == user_channel_id:
        return True
    
    return False
async def checks(ctx):
    """Do some checking."""
    
    # check if the user and the bot is in the same channel
    if not is_same_channel(ctx):
        await ctx.send("I am not with you. How dare you to command me like that.")
        return False
    
    return True

# other function
async def create_source(ctx, query):
    """Creates youtube_dl audio source for discord.py voice client."""
    
    try:
        async with ctx.typing(): # shows that the bot is typing in chat while searching for an audio source
            source = await YTDLSource.from_url(query, ctx.bot.loop) # creates a youtube_dl source
    except IndexError: # if found nothing
        await ctx.send("I found nothing with the given query..")
        return None
    
    return source

class Music(commands.Cog, name="music"):
    def __init__(self, bot):
        self.bot = bot
        self.guilds = Guilds() # collection of some guilds that this bot is currently in
    
    async def cog_command_error(self, ctx, error):
        """Catch all errors of this cog."""
        
        # a check on a command has failed
        if isinstance(error, commands.CheckFailure):
            await ctx.send("I'm not connected to any voice channel.")
        # ignore this error because it is already handled at the command itself
        elif isinstance(error, commands.errors.BadArgument):
            pass
        # otherwise, log all the other errors
        else:
            music_logger.exception(error)
            await ctx.send(error)
    
    @commands.command()
    async def join(self, ctx):
        """Invite me to your voice channel."""
        
        try:
            async with ctx.typing(): # shows that the bot is typing in chat while joining the voice channel
                await ctx.author.voice.channel.connect()
                await ctx.send("Alright, I joined your voice channel.")
        # user is not yet connected to a voice channel
        except AttributeError:
            await ctx.send(f"You must be connected to a voice channel first {ctx.author.name}.")
        # bot is already connected to a voice channel
        except discord.ClientException:
            if is_same_channel(ctx):
                await ctx.send("I'm already with you.")
            else:
                await ctx.send("I'm already with somebody else.")
    
    @commands.command()
    @commands.check(is_connected)
    async def leave(self, ctx):
        """Kick me out of your voice channel."""
        
        # do some checking before executing this command
        if not await checks(ctx):
            return
        
        # reset some bot's states
        self.guilds(ctx).has_played_voice = False # reset 'has_played_voice' state
        self.guilds(ctx).queue.clear() # reset the queue
        
        # finally, stop and disconnect the bot
        ctx.voice_client.stop() # stop the bot's voice
        await ctx.voice_client.disconnect() # disconnect the bot from voice channel
        await ctx.send("Ah, alright, cya.")
    
    async def play_source(self, ctx, vc, source):
        """Play an audio to a voice channel."""
        
        def play_next(error):
            """Executes when the voice client is done playing."""
            
            # log the errors if there is any
            if error:
                music_logger.exception(error)
                coroutine(ctx.send(error), self.bot.loop)
            
            # ensure that there is a song in queue
            if self.guilds(ctx).queue.queue:
                coroutine(ctx.invoke(self.bot.get_command("next")), self.bot.loop) # go to the next song
        
        vc.play(source, after=play_next) # play the voice to the voice channel
        await ctx.send(f"Now playing '{source.title}'.")
    
    @commands.command(aliases=("p", "stream"))
    async def play(self, ctx, *, query=""):
        """Play a song for you."""
        
        # check if the query argument is empty
        if not query:
            # if yes, cancel this command
            await ctx.send("What should I play?")
            return
        
        # check if this command is invoked using 'stream' alias
        if ctx.invoked_with == "stream":
            SIP = STREAM_INDICATOR_PREFIX # put prefix to the title of the source that indicates that it must be streamed
        else:
            SIP = ""
        
        # ensure that the bot is connected a voice channel
        try:
            # connect the bot to the user voice channel
            await ctx.author.voice.channel.connect()
        except AttributeError:
            # user is not yet connected to a voice channel
            await ctx.send(f"You must be connected to a voice channel first {ctx.author.name}.")
            return
        except discord.ClientException:
            pass # just ignore if bot is already connected to the voice channel
        
        # do some other checking before executing this command
        if not await checks(ctx):
            return
        
        # create the audio source
        source = await create_source(ctx, SIP + query)
        
        # ensure that there is actually a source
        if source:
            # initialize bot's states if the the queue is still empty
            if not self.guilds(ctx).queue.queue:
                self.guilds(ctx).has_played_voice = True # this means that the bot has played in the voice at least once
                self.guilds(ctx).queue.enqueue(SIP + source.title)
            
            # play the audio
            try:
                await self.play_source(ctx, ctx.voice_client, source)
            # enqueue the source if audio is already playing
            except discord.ClientException:
                self.guilds(ctx).queue.enqueue(SIP + source.title)
                await ctx.send(f"'{source.title}' is added to the queue.")
    
    @commands.command()
    @commands.check(is_connected)
    async def volume(self, ctx, *, vol=None):
        """Adjust my voice volume."""
        
        # do some checking before executing this command
        if not await checks(ctx):
            return
        
        vc = ctx.voice_client # get the voice client
        
        # ensure that the bot is playing voice in order to change the volume
        if not self.guilds(ctx).has_played_voice:
            await ctx.send("I haven't even started yet.")
            return
        elif vc.source is None:
            await ctx.send("I am not playing anything.")
            return
        
        # check if user has passed an argument
        if vol is None:
            await ctx.send("I expect an argument from 0 to 100.")
            return
        
        # cast string argument 'vol' into a float
        try:
            vol = float(vol)
        # except if the argument is not a number
        except ValueError:
            await ctx.send("The argument must only be a number.")
            return
        
        # set the volume
        if vol >= 0 and vol <= 100: # bound the volume from 0 to 100
            vc.source.volume = vol / 100
        else:
            await ctx.send("I expect a value from 0 to 100.")
    
    @commands.command()
    @commands.check(is_connected)
    async def pause(self, ctx):
        """Pause the song."""
        
        # do some checking before executing this command
        if not await checks(ctx):
            return
        
        vc = ctx.voice_client # get the voice client
        
        # ensure that the bot's voice is playing in order to pause
        if vc.is_playing():
            vc.pause()
            await ctx.send("Alright, paused.")
        # the bot haven't played yet
        elif not self.guilds(ctx).has_played_voice:
            await ctx.send("I haven't even started yet.")
        # there is no song in queue
        elif not self.guilds(ctx).queue.queue:
            await ctx.send("I am not playing anything.")
        else:
            await ctx.send("I already paused.")
    
    @commands.command()
    @commands.check(is_connected)
    async def resume(self, ctx):
        """Resume the song."""
        
        # do some checking before executing this command
        if not await checks(ctx):
            return
        
        vc = ctx.voice_client # get the voice client
        
        # ensure that the bot's voice is paused in order to resume
        if vc.is_paused():
            vc.resume()
            await ctx.send("Alright, song resumed")
        # the bot haven't played yet
        elif not self.guilds(ctx).has_played_voice:
            await ctx.send("I haven't even started yet.")
        # there is no song in queue
        elif not self.guilds(ctx).queue.queue:
            await ctx.send("I am not playing anything.")
        else:
            await ctx.send("I am not paused.")
    
    async def update_song(self, ctx):
        """Change the currently playing song."""
        
        vc = ctx.voice_client # get the voice client
        current = self.guilds(ctx).queue.current # get the current song in queue if there's any
        
        # ensure that the queue is not empty
        if current:
            source = await create_source(ctx, current) # create the audio source
        # the bot haven't played yet
        elif not self.guilds(ctx).has_played_voice:
            await ctx.send("I haven't even started yet.")
            return
        else:
            vc.stop() # stop the voice just to be sure
            await ctx.send("No more songs unfortunately.")
            return
        
        # if voice client is already playing, just change the source
        if vc.is_playing():
            vc.source = source
            await ctx.send(f"Now playing '{source.title}'.")
        # otherwise, play the source
        else:
            await self.play_source(ctx, vc, source)
    
    @commands.command()
    @commands.check(is_connected)
    async def next(self, ctx):
        """Skip the current song."""
        
        # do some checking before executing this command
        if not await checks(ctx):
            return
        
        self.guilds(ctx).queue.shift(1) # shift the queue to the left
        await self.update_song(ctx) # change the current song
    
    @commands.command()
    @commands.check(is_connected)
    async def prev(self, ctx):
        """Go back to the previous song."""
        
        # do some checking before executing this command
        if not await checks(ctx):
            return
        
        self.guilds(ctx).queue.shift(-1) # shift the queue to the right
        await self.update_song(ctx) # change the current song
    
    @commands.command()
    @commands.check(is_connected)
    async def removesong(self, ctx, *, index=1):
        """Remove a song in the queue."""
        
        # do some checking before executing this command
        if not await checks(ctx):
            return
        
        index -= 1 # decrement the 'index' to match the zero-based index of Python
        
        # if index is equal to 0, that means remove the currently playing song
        # do some extra stuff before removing the current song
        if index == 0:
            # try to remove a song in queue
            try:
                self.guilds(ctx).queue.dequeue() # dequeue a song in the queue
                self.guilds(ctx).queue.shift(-1) # shift the queue to the right so that the next song will be played instead of the next next song
                await ctx.invoke(self.bot.get_command("next")) # finally, play the next song
            # except when the queue is empty
            except IndexError:
                await ctx.send("I haven't even started yet.")
        # otherwise, just remove a song in queue
        else:
            # try to remove the song in queue
            try:
                self.guilds(ctx).queue.pop(index)
                await ctx.send("Song removed")
            # except if the song is not in the queue
            except IndexError:
                # check if the bot has not started playing yet
                if not self.guilds(ctx).has_played_voice:
                    await ctx.send("I haven't even started yet...")
                else:
                    await ctx.send(f"I can't remove that {ctx.author.name} because it doesn't exist.")
    @removesong.error
    async def remove_error(self, ctx, error):
        """Error handler for the 'remove' command."""
        
        # check if the argument is bad
        if isinstance(error, commands.errors.BadArgument):
            await ctx.send(f"I can't remove that {ctx.author.name}.")
            await ctx.send("The argument must only be a number or leave it none.")
    
    @commands.command()
    @commands.check(is_connected)
    async def stop(self, ctx):
        """Stop all the songs."""
        
        # do some checking before executing this command
        if not await checks(ctx):
            return
        
        vc = ctx.voice_client # get the voice client
        
        # ensure that the bot is connected to the voice client
        if vc.is_playing() or vc.is_paused():
            self.guilds(ctx).queue.clear() # reset the queue
            ctx.voice_client.stop() # stop the bot's voice
            await ctx.send("Playback stopped")
        # the bot haven't played yet
        elif not self.guilds(ctx).has_played_voice:
            await ctx.send("I haven't even started yet.")
        else:
            await ctx.send("I already stopped.")
    
    @commands.command()
    @commands.check(is_connected)
    async def queue(self, ctx):
        """Show the queue of songs."""
        
        SIP = STREAM_INDICATOR_PREFIX # shorten the variable name
        
        # do some checking before executing this command
        if not await checks(ctx):
            return
        
        # try to send the songs in the queue
        try:
            # format the queue to make it readable
            queue = [
                f"{i}." + (" (STREAM) " if q.startswith(SIP) else " ") + q.split(SIP)[-1]
                for i, q in enumerate(self.guilds(ctx).queue.queue, 1)
            ]
            
            await ctx.send("\n".join(queue))
        # except if it is empty
        except HTTPException:
            await ctx.send("No songs in queue.")

class YTDLSource(discord.PCMVolumeTransformer):
    """Creates a youtube_dl audio source with volume control."""
    
    def __init__(self, source, *, data, volume=1):
        super().__init__(source, volume)
        self.data = data
        self.title = data.get("title")
        self.url = data.get("url")
    
    @classmethod
    async def from_url(cls, url, loop):
        """Get source by URL."""
        
        # check if the URL is must be streamed
        if url.startswith(STREAM_INDICATOR_PREFIX):
            stream = True
        else:
            stream = False
        
        # get data from the given URL
        data = await loop.run_in_executor(
            None,
            (lambda:
                ytdl.extract_info(
                    url.split(STREAM_INDICATOR_PREFIX)[-1], # remove the prefix from the URL
                    download=not stream
                ))
        )
        ##$$$$ fix error somtimes
        # take the first item from the entries if there's any
        if "entries" in data:
            try:
                data = data["entries"][0]
            except Exception as e:
                music_logger.exception(e)
                return None
        
        filepath = data["url"] if stream else ytdl.prepare_filename(data) # source url or download path of the file, depends on the 'stream' parameter
        return cls(discord.FFmpegPCMAudio("C:/Users/Motzumoto/Desktop/AGB/ffmpeg/bin", **ffmpeg_options), data=data) # create and return the source

def setup(bot):
    bot.add_cog(Music(bot))