Nxt source code flaw reports

[Come-from-Beyond]

A SIGTERM shouldn't corrupt anything?

No idea, I prefer BareMetal OS. I don't like interface with a lot of icons.

[1714963349]

1714963349

[jkoil]

What information transactions.nxt contains?

Blockchain Explorer shows just timestamp, numbers, IDs for a transaction,
but transactions.nxt contain also names and http addresses.
Eg. "warhorse", "http://google.com", "paperwallet", "darkwallet", "cloudwallet", ...

[gsan1]

Line 6707:

Code:

counter++;
if (counter >= 255) {

    break;

}

Why is there a counter, so that only 255 transactions get returned? I know that this is the maximum amount of transactions in a block, but there is no reason why I could get more unconfirmed transactions by another peer, isn't it?

[nexern]

What information transactions.nxt contains?

Blockchain Explorer shows just timestamp, numbers, IDs for a transaction,
but transactions.nxt contain also names and http addresses.
Eg. "warhorse", "http://google.com", "paperwallet", "darkwallet", "cloudwallet", ...

these are attached aliases

[ferment]

A SIGTERM shouldn't corrupt anything?

No idea, I prefer BareMetal OS. I don't like interface with a lot of icons.

SIGTERM is the signal sent by Unix 'kill' command as the standard way to cleanly shutdown a process.

[Come-from-Beyond]

Line 6707:

Code:

counter++;
if (counter >= 255) {

    break;

}

Why is there a counter, so that only 255 transactions get returned? I know that this is the maximum amount of transactions in a block, but there is no reason why I could get more unconfirmed transactions by another peer, isn't it?

This is to limit volume of data sent between nodes.

[ricot]

A SIGTERM shouldn't corrupt anything?

No idea, I prefer BareMetal OS. I don't like interface with a lot of icons.

SIGTERM is the signal sent by Unix 'kill' command as the standard way to cleanly shutdown a process.

Taking a short look at the code, totally possible that it messes up everything.
Usually, you'd first write to a temporary file, and when it's finished you'd move it in place and therefore overwrite the old one, since that's only one atomic operation...
In case the process ends while writing, you just have a half-written temporary lying around.
This client doesn't do the moving thing, so as soon as you SIGKILL or even SIGTERM it while it's writing, it's in a bad state.

[LiQio]

hey ricot, thanks a lot for your work - just sent you a beer! cheers!

[ferment]

A SIGTERM shouldn't corrupt anything?

No idea, I prefer BareMetal OS. I don't like interface with a lot of icons.

SIGTERM is the signal sent by Unix 'kill' command as the standard way to cleanly shutdown a process.

Taking a short look at the code, totally possible that it messes up everything.
Usually, you'd first write to a temporary file, and when it's finished you'd move it in place and therefore overwrite the old one, since that's only one atomic operation...
In case the process ends while writing, you just have a half-written temporary lying around.
This client doesn't do the moving thing, so as soon as you SIGKILL or even SIGTERM it while it's writing, it's in a bad state.

Ok... brushed up on my Java and dove in:

Code:

	@Override
	public void destroy() {
		
		scheduledThreadPool.shutdown();
		cachedThreadPool.shutdown();
		
		try {
			
			Block.saveBlocks("blocks.nxt");
			
		} catch (Exception e) { }
		try {
			
			Transaction.saveTransactions("transactions.nxt");
			
		} catch (Exception e) { }
		
		try {
			
			blockchainChannel.close();
			
		} catch (Exception e) { }
		
		logMessage("Nxt stopped.");
		
	}
	
}

Since scheduledThreadPool.shutdown() (and cachedThreadPool) doesn't wait for the threads to actually finish before returning, it might create a condition where saveBlocks blocks the threads that are trying to shutdown due to the synchronized on blocks. So it might be possible for destroy() to exit before the thread pools have completely shutdown, which could cause corruption of blocks.nxt if something bad happens in the threads.

The fix is to call awaitTermination on the threadpools before call Block.saveBlocks.

[Jean-Luc]

The fix is to call awaitTermination on the threadpools before call Block.saveBlocks.

This has been fixed since 0.4.9e. Waiting up to 10 s, then shutdownNow.

[ferment]

The fix is to call awaitTermination on the threadpools before call Block.saveBlocks.

This has been fixed since 0.4.9e. Waiting up to 10 s, then shutdownNow.

Guess that's not what is killing 80% of my nodes. heh.

[klee]

smaragda, ricot, vamdor, ImmortAlex, rlh: Please PM your NXT tip account. Thanks for pouring through the code.

FrictionlessCoin send yours too cuz you need a NXT hug.

Post your addresses guys (gals?) I wanna reward your efforts...

ricot : 100K
ImmortAlex :50K
vamdor: 50K
rlh: 50K
smaragda: 50K

[Come-from-Beyond]

smaragda, ricot, vamdor, ImmortAlex, rlh: Please PM your NXT tip account. Thanks for pouring through the code.

FrictionlessCoin send yours too cuz you need a NXT hug.

Post your addresses guys (gals?) I wanna reward your efforts...

ricot : 100K
ImmortAlex :50K
vamdor: 50K
rlh: 50K
smaragda: 50K

What about FrictionlessCoin?

[klee]

smaragda, ricot, vamdor, ImmortAlex, rlh: Please PM your NXT tip account. Thanks for pouring through the code.

FrictionlessCoin send yours too cuz you need a NXT hug.

Post your addresses guys (gals?) I wanna reward your efforts...

ricot : 100K
ImmortAlex :50K
vamdor: 50K
rlh: 50K
smaragda: 50K

What about FrictionlessCoin?

I will pay him in his scamcoin

[utopianfuture]

smaragda, ricot, vamdor, ImmortAlex, rlh: Please PM your NXT tip account. Thanks for pouring through the code.

FrictionlessCoin send yours too cuz you need a NXT hug.

Post your addresses guys (gals?) I wanna reward your efforts...

ricot : 100K
ImmortAlex :50K
vamdor: 50K
rlh: 50K
smaragda: 50K

That's great klee. I hope you would be NXT billionaire in two years. Don't forget to helicopter me to your private island at that time   

[klee]

Post your addresses guys (gals?) I wanna reward your efforts...

ricot : 100K
ImmortAlex :50K
vamdor: 50K
rlh: 50K
smaragda: 50K

Is this for real?!?      TRULY APPRECIATED!  


...address is in my signature...

Check!

[klee]

smaragda, ricot, vamdor, ImmortAlex, rlh: Please PM your NXT tip account. Thanks for pouring through the code.

FrictionlessCoin send yours too cuz you need a NXT hug.

Post your addresses guys (gals?) I wanna reward your efforts...

ricot : 100K
ImmortAlex :50K
vamdor: 50K
rlh: 50K
smaragda: 50K

That's great klee. I hope you would be NXT billionaire in two years. Don't forget to helicopter me to your private island at that time   

You will be in my VIP list 

[BloodyRookie]

smaragda, ricot, vamdor, ImmortAlex, rlh: Please PM your NXT tip account. Thanks for pouring through the code.

FrictionlessCoin send yours too cuz you need a NXT hug.

Post your addresses guys (gals?) I wanna reward your efforts...

ricot : 100K
ImmortAlex :50K
vamdor: 50K
rlh: 50K
smaragda: 50K

Hey, I am a nice guy too

[Come-from-Beyond]

Hey CfB... ricot helped me put my concerns from my previous post into perspective...

https://bitcointalk.org/index.php?topic=397183.msg4342184#msg4342184


Would it be more secure for the network if all initial founding accounts were restricted from forging (after funds have been transferred in other accounts of course)?

It changes nothing.

[instacalm]

smaragda, ricot, vamdor, ImmortAlex, rlh: Please PM your NXT tip account. Thanks for pouring through the code.

FrictionlessCoin send yours too cuz you need a NXT hug.

Post your addresses guys (gals?) I wanna reward your efforts...

ricot : 100K
ImmortAlex :50K
vamdor: 50K
rlh: 50K
smaragda: 50K

Greetings to sunny Greece.