This adds support for notifying systemd about the state of LND. It
notifies systemd just before waiting for wallet password or, if
`wallet-password-file` was specified, right after unlocking the wallet.
This means that "ready" represents RPC being available for intended use.
It's intentional, so that client services can use `After=` in `systemd`
configuration to avoid misleading error messages about missing files or
refused connections.
Part of #4470
In lnd, log messages about channels are generally logged with a
reference to their channel point rather than the short channel id.
Channel point is reorg-resistant and also easier to look up in for
example a block explorer.
In the link however, all log messages are accompanied by short channel
id. This makes it difficult to grep a log for all channel activity. The
PEER message for example which are often crucial to analyse, are logged
with channel points.
This commit modifies the link logging to also use channel points.
Improve 'ErrReservedValueInvalidated' error string to explain that the
error is triggered by a transaction that would deplete funds reserved for
potential future anchor channel closings (via CPFP)
Add hint that further details can be found in the debug log
Update strings in 'lntest/itest/log_error_whitelist.txt' correspondingly
Since we don't really do anything with the errors we check in the itest
error whitelist but get a lot of failed Travis runs because of it, we
disable the check for the moment.
This removes a warning in the documentation saying that pruned nodes are
not supported. This is no longer the case as [pruning is supported since
0.13](https://github.com/lightningnetwork/lnd/pull/5154). So instead it
now says pruning is supported and notes the version and implications of
pruning.
This changes file reation mode on admin macaroon from 0600 to 0640. The
reason is to make permission management easier.
Closes#4385
**Is this safe?**
Yes, it is. Assuming a reasonably secure Linux system, it will have a
separate group for each user. E.g. a new user `lnd` gets assigned group
`lnd` which nothing else belongs to. A system that does not do this is
inherently broken already.
Since there is no other user in the group, no other user can read admin
macaroon unless the administrator explicitly allowed it. Thus there's no
harm allowing group read.
