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Commit Graph

14 Commits

Author SHA1 Message Date
Simon Tatham
947962e0b9 Revamp of EOF handling in all network connections, pipes and other
data channels. Should comprehensively fix 'half-closed', in principle,
though it's a big and complicated change and so there's a good chance
I've made at least one mistake somewhere.

All connections should now be rigorous about propagating end-of-file
(or end-of-data-stream, or socket shutdown, or whatever) independently
in both directions, except in frontends with no mechanism for sending
explicit EOF (e.g. interactive terminal windows) or backends which are
basically always used for interactive sessions so it's unlikely that
an application would be depending on independent EOF (telnet, rlogin).

EOF should now never accidentally be sent while there's still buffered
data to go out before it. (May help fix 'portfwd-corrupt', and also I
noticed recently that the ssh main session channel can accidentally
have MSG_EOF sent before the output bufchain is clear, leading to
embarrassment when it subsequently does send the output).

[originally from svn r9279]
2011-09-13 11:44:03 +00:00
Simon Tatham
201c2c295b Patch from Gert-Jan Vons: create an event handle to go in the
OVERLAPPED structure in output threads, as we already do for input
threads. This apparently sorts out a hanging issue with serial ports
when trying to do simultaneous read and write, because (GJV says,
and it sounds plausible to me) in the absence of that event object
Windows signals the file handle itself to notify GetOverlappedResult
that it can return - and since the file handle might be being
signalled by a read operation instead, that leads to ambiguity.
Using an explicit event object in both directions means Windows
always knows which way the data is going.

Also a trivial fix in handle_output_new(), which was referencing the
wrong element of a union due to a copy and paste error. (Since the
result was address-taken and cast to void *, this wasn't a
functional error, but it was conceptually wrong.)

[originally from svn r8410]
2009-01-12 20:41:28 +00:00
Simon Tatham
5f410ef051 In the wake of r7415, let's have some better error reporting.
Instead of passing -1 to its gotdata and sentdata callbacks on
error, winhandl.c will now pass the negation of the Windows error
number; and the Plink front end will now format that into an error
message and pass it on to the user.

[originally from svn r7416]
[r7415 == 702a92ceb8]
2007-03-27 19:10:10 +00:00
Simon Tatham
702a92ceb8 Windows apparently sends ERROR_BROKEN_PIPE when a pipe we're reading
from is closed normally from the writing end. This is ludicrous; if
that situation isn't a natural EOF, _nothing_ is. So if we get that
particular error, we pretend it's EOF.

[originally from svn r7415]
2007-03-27 18:49:59 +00:00
Jacob Nevins
46a8859541 Fix Plink, the serial backend, and local-proxy support on Win98SE (at least),
which have been broken since r6797.
(At least some versions of Win9x are gratuitously picky about the arguments to
CreateThread(), requiring lpThreadId not to be NULL.)

[originally from svn r7132]
[r6797 == 291533d3f9]
2007-01-21 23:34:35 +00:00
Simon Tatham
33e827818a Add a mini-rant to the top comment explaining why threads are
required. (I just tried getting rid of them; it worked fine for
serial ports, but not for anything else. The Windows I/O API sucks.)

[originally from svn r6843]
2006-09-03 12:55:16 +00:00
Simon Tatham
a485923ae4 Reading 4K at a time from a serial port turns out to be a bit
unfriendly in an interactive session, because at 19200 baud it takes
nearly two seconds to receive that much data, and as long as the
data is flowing continuously Windows waits until it has a full
buffer. So here's another annoying flag in the winhandl API, which
restricts reads to length 1 so that serial output shows up as it
appears.

(I tried this yesterday, but without the OVERLAPPED fix in r6826 it
behaved very erratically. It now seems solid.)

[originally from svn r6827]
[r6826 == 2aedc83f8d]
2006-08-28 18:26:50 +00:00
Simon Tatham
2aedc83f8d Apparently it helps for an OVERLAPPED structure to contain a valid
event handle. This seems to have fixed _some_, but not all, of the
curious data loss issues in the Windows serial backend.

[originally from svn r6826]
2006-08-28 18:16:49 +00:00
Simon Tatham
17bc654532 Grow some nasty warts on the side of winhandl.c, in preparation for
a serial port backend:
 - In order to do simultaneous reading and writing on the same
   HANDLE, you must enable overlapped access and pass an OVERLAPPED
   structure to each ReadFile and WriteFile call. This would make
   sense if it were an optional thing I could do if I wanted to do
   the reading and writing in the same thread, but making it
   mandatory even if I'm doing them in _different_ threads is just
   annoying and arbitrary.
 - Serial ports occasionally return length 0 from ReadFile, for no
   particularly good reason. Fortunately serial ports also don't
   have a real EOF condition to speak of, so ignoring EOFs is
   actually a viable response in spite of sounding utterly gross.
Hence, handle_{input,output}_new() now accept a flags parameter,
which includes a flag to enable the OVERLAPPED bureaucracy and a
flag to cause EOFs to be ignored on input handles. The current
clients of winhandl.c do not use either of these.

[originally from svn r6813]
2006-08-27 10:00:36 +00:00
Simon Tatham
421a5ece2c We _can_ have handle_throttle() called on defunct handles after all,
so it should just do nothing rather than failing an assertion.

[originally from svn r6807]
2006-08-26 10:58:13 +00:00
Simon Tatham
d5f4ce4611 Another bug fix: always set the busy flag when telling a subthread
to do something, otherwise handle_get_events will forget to tell the
front end to check for that subthread finishing. This applies even
when we're only setting `busy' to tell the subthread to terminate!

[originally from svn r6805]
2006-08-26 10:19:23 +00:00
Simon Tatham
911f43b872 Bug fix: since the input thread does not wait for the event object
until _after_ its first read, we should not start by signalling that
object in order to trigger the first read. Ahem.

[originally from svn r6799]
2006-08-26 08:15:53 +00:00
Simon Tatham
52cdcc6a7c Small tweak to the new handle API: provide a `privdata' field in
each handle structure, set on initialisation and readable by an API
call.

[originally from svn r6798]
2006-08-26 07:41:15 +00:00
Simon Tatham
291533d3f9 New piece of Windows infrastructure: winhandl.c takes Plink's
thread-based approach to stdin and stdout, wraps it in a halfway
sensible API, and makes it a globally available service across all
network tools.

There is no direct functionality enhancement from this checkin:
winplink.c now talks to the new API instead of doing it all
internally, but does nothing different as a result.

However, this should lay the groundwork for several diverse pieces
of work in future: pipe-based ProxyCommand on Windows, a serial port
back end, and (hopefully) a pipe-based means of communicating with
Pageant, which should have sensible blocking behaviour and hence
permit asynchronous agent requests and decrypt-on-demand.

[originally from svn r6797]
2006-08-25 22:10:16 +00:00