This is working towards allowing the subsidiary SSH connection in an
SshProxy to share the main user-facing Seat, so as to be able to pass
through interactive prompts.
This is more difficult than the similar change with LogPolicy, because
Seats are stateful. In particular, the trust-sigil status will need to
be controlled by the SshProxy until it's ready to pass over control to
the main SSH (or whatever) connection.
To make this work, I've introduced a thing called a TempSeat, which is
(yet) another Seat implementation. When a backend hands its Seat to
new_connection(), it does it in a way that allows new_connection() to
borrow it completely, and replace it in the main backend structure
with a TempSeat, which acts as a temporary placeholder. If the main
backend tries to do things like changing trust status or sending
output, the TempSeat will buffer them; later on, when the connection
is established, TempSeat will replay the changes into the real Seat.
So, in each backend, I've made the following changes:
- pass &foo->seat to new_connection, which may overwrite it with a
TempSeat.
- if it has done so (which we can tell via the is_tempseat() query
function), then we have to free the TempSeat and reinstate our main
Seat. The signal that we can do so is the PLUGLOG_CONNECT_SUCCESS
notification, which indicates that SshProxy has finished all its
connection setup work.
- we also have to remember to free the TempSeat if our backend is
disposed of without that having happened (e.g. because the
connection _doesn't_ succeed).
- in backends which have no local auth phase to worry about, ensure
we don't call seat_set_trust_status on the main Seat _before_ it
gets potentially replaced with a TempSeat. Moved some calls of
seat_set_trust_status to just after new_connection(), so that now
the initial trust status setup will go into the TempSeat (if
appropriate) and be buffered until that seat is relinquished.
In all other uses of new_connection, where we don't have a Seat
available at all, we just pass NULL.
This is NFC, because neither new_connection() nor any of its delegates
will _actually_ do this replacement yet. We're just setting up the
framework to enable it to do so in the next commit.
Now new_connection() takes an optional LogPolicy * argument, and
passes it on to the SshProxy setup. This means that SshProxy's
implementation of the LogPolicy trait can answer queries like
askappend() and logging_error() by passing them on to the same
LogPolicy used by the main backend.
Not all callers of new_connection have a LogPolicy, so we still have
to fall back to the previous conservative default behaviour if
SshProxy doesn't have a LogPolicy it can ask.
The main backend implementations didn't _quite_ have access to a
LogPolicy already, but they do have a LogContext, which has a
LogPolicy vtable pointer inside it; so I've added a query function
log_get_policy() which allows them to extract that pointer to pass to
new_connection.
This is the first step of fixing the non-interactivity limitations of
SshProxy. But it's also the easiest step: the next ones will be more
involved.
This gets rid of all those annoying 'win', 'ux' and 'gtk' prefixes
which made filenames annoying to type and to tab-complete. Also, as
with my other recent renaming sprees, I've taken the opportunity to
expand and clarify some of the names so that they're not such cryptic
abbreviations.
