`resource temporarily unavailable` needs a better error

[jackzampolin]

This error currently happens when the lcd is running and you try to use gaiacli on the same machine to access the keystore. Perhaps list the resource and mention that its likely being used by a running process. Suggest fixes to the issue such as shutting down the process (likely the lcd)

[mslipper]

I took at look at this one. resource temporarily unavailable is coming from LevelDB's underlying filesystem lock. That lock is created by the flock(2) Linux syscall. We can determine if that lock is in place via the following methods:

1. EWOULDBLOCK is returned by the kernel when attempting a flock of our own. We'd need to unlock the FS again afterwards.
2. We run a regex (or something similar) over the error message.

Both cases are tough from a portability/maintainability perspective. I recommend adding documentation around this outside of the daemon itself.

[alexanderbez]

Nice digging @mslipper 👍

[jackzampolin]

Agreed @mslipper Thanks for digging into this. I've opened an issue to track that.