This looks like a regression. Has it been tested after the changes have been made?

I haven't looked deeper into this but -ne looks like it should be applied to an integer. But "0" isn't an integer, it's a string.

I haven't looked deeper into this but -ne looks like it should be applied to an integer. But "0" isn't an integer, it's a string.

I don't think this is the reason. "0" is also treated as an integer 🤔

This looks like a regression. Has it been tested after the changes have been made?

It seems it wasn't tested.
But I did test it on Friday.

I haven't looked deeper into this but -ne looks like it should be applied to an integer. But "0" isn't an integer, it's a string.

This is not the issue.
The code block gets executed, but the value of DELAY is always zero I tried this on OpenWrt 21, I tried also the old code and it also does not work, it could have to do something with my device or with OpenWrt 21 / or better said the busybox version used by OpenWrt which may have changed this part of the random generation of numbers.

I just tested the bootup delay in openwisp-config based on 8b85ca5 on OpenWrt 19.07 and it works fine.

So the issue must have appeared through changes after that.

I'm going to test a more recent version as well.

I don't know what I'm missing, but it's working fine here also with a quite recent version: d65be8c on OpenWrt 21.02.

The RANDOM function is also working as expected if called from a shell:

root@VR-2020 /etc/config # BOOTUP_DELAY=60
root@VR-2020 /etc/config # echo "$((RANDOM % BOOTUP_DELAY))"
35
root@VR-2020 /etc/config # echo "$((RANDOM % BOOTUP_DELAY))"
51
root@VR-2020 /etc/config # echo "$((RANDOM % BOOTUP_DELAY))"
10
root@VR-2020 /etc/config # echo "$((RANDOM % BOOTUP_DELAY))"
50
root@VR-2020 /etc/config # echo "$((RANDOM % BOOTUP_DELAY))"
34
root@VR-2020 /etc/config # echo "$((RANDOM % BOOTUP_DELAY))"
59

We enable Ash random support by setting BUSYBOX_DEFAULT_ASH_RANDOM_SUPPORT=y. In upstream OpenWrt this is not enabled: https://github.com/openwrt/openwrt/blob/master/package/utils/busybox/Config-defaults.in#L2994
So we will need to change the implementation to get along without RANDOM.

We enable Ash random support by setting BUSYBOX_DEFAULT_ASH_RANDOM_SUPPORT=y. In upstream OpenWrt this is not enabled: https://github.com/openwrt/openwrt/blob/master/package/utils/busybox/Config-defaults.in#L2994 So we will need to change the implementation to get along without RANDOM.

This explains it, thanks.

We could use awk, there's a few examples on stackoverflow, will the seed be good enough?
Alternatively we can add a lua script.

This works on bash to calculate a kind of random delay value:

okraits:~/ (master✗) $ echo "$((60/100.0*$(head /dev/urandom| tr -dc '[:digit:]' | head -c 2)))"                                [21:21:12]
27.
okraits:~/ (master✗) $ echo "$((60/100.0*$(head /dev/urandom| tr -dc '[:digit:]' | head -c 2)))"                                [21:21:13]
59.399999999999999
okraits:~/ (master✗) $ echo "$((60/100.0*$(head /dev/urandom| tr -dc '[:digit:]' | head -c 2)))"                                [21:21:14]
16.800000000000001
okraits:~/ (master✗) $ echo "$((60/100.0*$(head /dev/urandom| tr -dc '[:digit:]' | head -c 2)))"                                [21:21:15]
25.800000000000001
okraits:~/ (master✗) $ echo "$((60/100.0*$(head /dev/urandom| tr -dc '[:digit:]' | head -c 2)))"                                [21:21:16]
9.5999999999999996

I will try it with ash/busybox tomorrow.

You can't do float math in ash and bc is not available either. I suggest using a lua script:

• Call math.randomseed with some input from /dev/urandom
• Use math.random to get a random number

@okraits https://stackoverflow.com/questions/4678836/how-to-generate-random-numbers-under-openwrt

@nemesisdesign This works fine. We can use this instead of RANDOM

A solution is almost ready in #171.