This commit DOES NOT compile.
This change alters these module interface calls:-
1) mod_server_monitor_resize() (Call from xrdp to module). Updated.
2) server_reset() (Call from module to xrdp). Replaced.
The mod_server_monitor_resize() call is updated :-
1) to allow a monitor list to be passed in for a multimon resize
2) with an 'in_progress' return value which tells the caller whether or
not to expect a callback.
The server_reset() call served two purposes up until now:-
1) To allow a module to resize a single monitor session. There
is no way to request a multi-monitor resize from the module
2) (with bpp == 0) To signal to the mm resize state machine that
a server screen resize hsa finished.
This is split into two calls:-
1) client_monitor_resize() to allow a mdule to request a
multimon resize.
2) server_monitor_resize_done(). This is called by a module
when a resize is completed.
There are a number of ways the existing transport connect logic in
trans_connect could be improved for POSIX compatibility, and also
slightly tidied up:-
1) The same socket is re-used for multiple connect attempts following
failure which isn't behaviour defined by POSIX.1-2017 (although it
works on Linux).
2) An asynchronous connect is started, and then after a short
delay connect() is called again on the same socket. POSIX.1-2017
is clear that in this situation EALREADY is returned before the
connection is established, but is silent on the behaviour expected
when the connection is established. Returning success is an option,
but so is returning EISCONN. The current code assumes the connect()
call will succeed.
3) The code contains two virtually identical, quite complex loops for
TCP and UNIX sockets, differing only in the calls to create a socket
and connect it.
4) trans_connect() contains looping and retry logic, but this isn't
seen as sufficient by the chansrv connect code in xrdp/xrdp_mm.c and
the Xorg connect code in xup/xup.c. Both of these implement their own
looping and retry logic on top of the logic in trans_connect(),
resulting in slightly unpredictable behaviour with regard to
timeouts.
5) A socket number can technically be zero, but in a couple of places
this isn't allowed for.
This PR attempts to correct the implementation of trans_connect(),
and also to simplify the areas it is called from.
As part of the PR, the signature of the server_is_term member of the
xrdp module interface is changed to match the signature expected by the
is_term member of a struct trans. This allows for trans_connect()
in xrdp modules to directly access g_is_term() within the main xrdp
executable. At the moment this functionality is only used by the xup
module.
matt335672