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2ca0070f89
I've tried to separate out as many individually coherent changes from this work as I could into their own commits, but here's where I run out and have to commit the rest of this major refactoring as a big-bang change. Most of ssh.c is now no longer in ssh.c: all five of the main coroutines that handle layers of the SSH-1 and SSH-2 protocols now each have their own source file to live in, and a lot of the supporting functions have moved into the appropriate one of those too. The new abstraction is a vtable called 'PacketProtocolLayer', which has an input and output packet queue. Each layer's main coroutine is invoked from the method ssh_ppl_process_queue(), which is usually (though not exclusively) triggered automatically when things are pushed on the input queue. In SSH-2, the base layer is the transport protocol, and it contains a pair of subsidiary queues by which it passes some of its packets to the higher SSH-2 layers - first userauth and then connection, which are peers at the same level, with the former abdicating in favour of the latter at the appropriate moment. SSH-1 is simpler: the whole login phase of the protocol (crypto setup and authentication) is all in one module, and since SSH-1 has no repeat key exchange, that setup layer abdicates in favour of the connection phase when it's done. ssh.c itself is now about a tenth of its old size (which all by itself is cause for celebration!). Its main job is to set up all the layers, hook them up to each other and to the BPP, and to funnel data back and forth between that collection of modules and external things such as the network and the terminal. Once it's set up a collection of packet protocol layers, it communicates with them partly by calling methods of the base layer (and if that's ssh2transport then it will delegate some functionality to the corresponding methods of its higher layer), and partly by talking directly to the connection layer no matter where it is in the stack by means of the separate ConnectionLayer vtable which I introduced in commit 8001dd4cb, and to which I've now added quite a few extra methods replacing services that used to be internal function calls within ssh.c. (One effect of this is that the SSH-1 and SSH-2 channel storage is now no longer shared - there are distinct struct types ssh1_channel and ssh2_channel. That means a bit more code duplication, but on the plus side, a lot fewer confusing conditionals in the middle of half-shared functions, and less risk of a piece of SSH-1 escaping into SSH-2 or vice versa, which I remember has happened at least once in the past.) The bulk of this commit introduces the five new source files, their common header sshppl.h and some shared supporting routines in sshcommon.c, and rewrites nearly all of ssh.c itself. But it also includes a couple of other changes that I couldn't separate easily enough: Firstly, there's a new handling for socket EOF, in which ssh.c sets an 'input_eof' flag in the BPP, and that responds by checking a flag that tells it whether to report the EOF as an error or not. (This is the main reason for those new BPP_READ / BPP_WAITFOR macros - they can check the EOF flag every time the coroutine is resumed.) Secondly, the error reporting itself is changed around again. I'd expected to put some data fields in the public PacketProtocolLayer structure that it could set to report errors in the same way as the BPPs have been doing, but in the end, I decided propagating all those data fields around was a pain and that even the BPPs shouldn't have been doing it that way. So I've reverted to a system where everything calls back to functions in ssh.c itself to report any connection- ending condition. But there's a new family of those functions, categorising the possible such conditions by semantics, and each one has a different set of detailed effects (e.g. how rudely to close the network connection, what exit status should be passed back to the whole application, whether to send a disconnect message and/or display a GUI error box). I don't expect this to be immediately perfect: of course, the code has been through a big upheaval, new bugs are expected, and I haven't been able to do a full job of testing (e.g. I haven't tested every auth or kex method). But I've checked that it _basically_ works - both SSH protocols, all the different kinds of forwarding channel, more than one auth method, Windows and Linux, connection sharing - and I think it's now at the point where the easiest way to find further bugs is to let it out into the wild and see what users can spot.
This is the README for the source archive of PuTTY, a free Windows
and Unix Telnet and SSH client.
If you want to rebuild PuTTY from source, we provide a variety of
Makefiles and equivalents. (If you have fetched the source from
Git, you'll have to generate the Makefiles yourself -- see
below.)
There are various compile-time directives that you can use to
disable or modify certain features; it may be necessary to do this
in some environments. They are documented in `Recipe', and in
comments in many of the generated Makefiles.
For building on Windows:
- windows/Makefile.vc is for command-line builds on MS Visual C++
systems. Change into the `windows' subdirectory and type `nmake
-f Makefile.vc' to build all the PuTTY binaries.
As of 2017, we successfully compile PuTTY with both Visual Studio
7 (2003) and Visual Studio 14 (2015), so our guess is that it will
probably build with versions in between those as well.
(The binaries from Visual Studio 14 are only compatible with
Windows XP and up. Binaries from Visual Studio 7 ought to work
with anything from Windows 95 onward.)
- Inside the windows/MSVC subdirectory are MS Visual Studio project
files for doing GUI-based builds of the various PuTTY utilities.
These have been tested on Visual Studio 7 and 10.
You should be able to build each PuTTY utility by loading the
corresponding .dsp file in Visual Studio. For example,
MSVC/putty/putty.dsp builds PuTTY itself, MSVC/plink/plink.dsp
builds Plink, and so on.
- windows/Makefile.mgw is for MinGW / Cygwin installations. Type
`make -f Makefile.mgw' while in the `windows' subdirectory to
build all the PuTTY binaries.
MinGW and friends can lag behind other toolchains in their support
for the Windows API. Compile-time levers are provided to exclude
some features; the defaults are set appropriately for the
'mingw-w64' cross-compiler provided with Ubuntu 14.04. If you are
using an older toolchain, you may need to exclude more features;
alternatively, you may find that upgrading to a recent version of
the 'w32api' package helps.
- windows/Makefile.lcc is for lcc-win32. Type `make -f
Makefile.lcc' while in the `windows' subdirectory. (You will
probably need to specify COMPAT=-DNO_MULTIMON.)
- Inside the windows/DEVCPP subdirectory are Dev-C++ project
files for doing GUI-based builds of the various PuTTY utilities.
The PuTTY team actively use Makefile.vc (with VC7/10) and Makefile.mgw
(with mingw32), so we'll probably notice problems with those
toolchains fairly quickly. Please report any problems with the other
toolchains mentioned above.
For building on Unix:
- unix/configure is for Unix and GTK. If you don't have GTK, you
should still be able to build the command-line utilities (PSCP,
PSFTP, Plink, PuTTYgen) using this script. To use it, change into
the `unix' subdirectory, run `./configure' and then `make'. Or you
can do the same in the top-level directory (we provide a little
wrapper that invokes configure one level down), which is more like
a normal Unix source archive but doesn't do so well at keeping the
per-platform stuff in each platform's subdirectory; it's up to you.
- unix/Makefile.gtk and unix/Makefile.ux are for non-autoconfigured
builds. These makefiles expect you to change into the `unix'
subdirectory, then run `make -f Makefile.gtk' or `make -f
Makefile.ux' respectively. Makefile.gtk builds all the programs but
relies on Gtk, whereas Makefile.ux builds only the command-line
utilities and has no Gtk dependence.
- For the graphical utilities, any of Gtk+-1.2, Gtk+-2.0, and Gtk+-3.0
should be supported. If you have more than one installed, you can
manually specify which one you want by giving the option
'--with-gtk=N' to the configure script where N is 1, 2, or 3.
(The default is the newest available, of course.) In the absence
of any Gtk version, the configure script will automatically
construct a Makefile which builds only the command-line utilities;
you can manually create this condition by giving configure the
option '--without-gtk'.
- pterm would like to be setuid or setgid, as appropriate, to permit
it to write records of user logins to /var/run/utmp and
/var/log/wtmp. (Of course it will not use this privilege for
anything else, and in particular it will drop all privileges before
starting up complex subsystems like GTK.) By default the makefile
will not attempt to add privileges to the pterm executable at 'make
install' time, but you can ask it to do so by running configure
with the option '--enable-setuid=USER' or '--enable-setgid=GROUP'.
- The Unix Makefiles have an `install' target. Note that by default
it tries to install `man' pages; if you have fetched the source via
Git then you will need to have built these using Halibut
first - see below.
- It's also possible to build the Windows version of PuTTY to run
on Unix by using Winelib. To do this, change to the `windows'
directory and run `make -f Makefile.mgw CC=winegcc RC=wrc'.
All of the Makefiles are generated automatically from the file
`Recipe' by the Perl script `mkfiles.pl' (except for the Unix one,
which is generated by the `configure' script; mkfiles.pl only
generates the input to automake). Additions and corrections to Recipe,
mkfiles.pl and/or configure.ac are much more useful than additions and
corrections to the actual Makefiles, Makefile.am or Makefile.in.
The Unix `configure' script and its various requirements are generated
by the shell script `mkauto.sh', which requires GNU Autoconf, GNU
Automake, and Gtk; if you've got the source from Git rather
than using one of our source snapshots, you'll need to run this
yourself. The input file to Automake is generated by mkfiles.pl along
with all the rest of the makefiles, so you will need to run mkfiles.pl
and then mkauto.sh.
Documentation (in various formats including Windows Help and Unix
`man' pages) is built from the Halibut (`.but') files in the `doc'
subdirectory using `doc/Makefile'. If you aren't using one of our
source snapshots, you'll need to do this yourself. Halibut can be
found at <https://www.chiark.greenend.org.uk/~sgtatham/halibut/>.
The PuTTY home web site is
https://www.chiark.greenend.org.uk/~sgtatham/putty/
If you want to send bug reports or feature requests, please read the
Feedback section of the web site before doing so. Sending one-line
reports saying `it doesn't work' will waste your time as much as
ours.
See the file LICENCE for the licence conditions.