V0.7.12 actix-web::ws can not run in arm-linux

[lygz5016]

The run error message:

thread 'main' panicked at 'could not initialize thread_rng: All entropy sources failed (permanently unavailable); cause: OS RNG not yet seeded (not ready yet); cause: Resource temporarily unavailable (os error 11)'

Where thread_rng is used in the source code:

1. src/ws/frame.rs line: 329 let mask = rand::random::<u32>();
2. src/ws/client.rs line: 302 let sec_key: [u8; 16] = rand::random();

Only use ReadRng on my target(arm-unknown-linux-gnueabi):
let mut rng = read::ReadRng::new(std::fs::File::open("/dev/urandom").unwrap());

[fafhrd91]

i dont know how to fix this.

@DoumanAsh any ideas?

[DoumanAsh]

@lygz5016 Are you use we cannot use at least EntropyRng?

Disregard that, I looked at source code for ThreadRng and it uses EntropyRng

I feel like it is strange that it is not possible to use it on your system since it is still Linux with /dev/urandom I wonder if there is similar issue in rand crate

[DoumanAsh]

This PR might help with such issues rust-random/rand#579

It would allow user to set own source of entropy.
I don't think we should get away from using thread_rng, but it is still questionable why it fails on arm linux.

[lygz5016]

@DoumanAsh I tried to use EntropyRng, but it still can't work.

The use of OsRng is blocked.

So I can only use read::ReadRng::new(std::fs::File::open("/dev/urandom").unwrap());

I don't think we should get away from using thread_rng, too.

[DoumanAsh]

I think it might be worth asking from rand guys about it.
Since your target is linux I'm surprised that EntropyRng fails...

[lygz5016]

This is a very strange question. I'm not sure if it's a system cause, and it could not initialize without an entropy source.

[DoumanAsh]

It would explain the OsRng problem, but EntropyRng is intended to work on common systems as guaranteed way to initialize random(when HW's random fails you)

In any case I would prefer to not move away from thread_rng itself, I'll try to check rand crate myself on my raspberry pi.

[fafhrd91]

@DoumanAsh can we do anything?

[DoumanAsh]

I think we cannot unless random's author will tell that EntropyRng cannot be used on arm platform.
Otherwise we could only do platform specific code as @lygz5016 suggested, but I don't like this idea

[fafhrd91]

@DoumanAsh thanks