Okay, I went WAY too far down the rabbit hole on this one. Here is my result of trying to get all these dependencies compiled (note: I'm trying to use Visual Studio for the compile, I didn't even look at MinGW)...

To compile libgit2 with SSH, we need libssh2. libssh2 requires openssl or gcrypt.

openssl uses a custom perl build system to call the compiler/linker directly (no VS solutions), but still can be easily scripted:

perl Configure VC-WIN32 no-asm --prefix="C:\OpenSSL-Win32"
ms\do_ms.bat
nmake -f ms\ntdll.mak
nmake -f ms\ntdll.mak install

libssh2 has an old VS6 project (.dsp), which when I converted to VS I was able to compile fine. However, it would be difficult to get this to compile from a script directly from sources without including our own newer project file or script the entire build.
I didn't really try to use libgcrypt, but it seems the only way it provides to build it on Windows would be to use MinGW.

The main problem that I ran into was that libgit2 would not link against the libssh2 library unless I changed libssh2's calling convention from __cdecl to __stdcall. However, if I did that then I couldn't link against OpenSSL. Attempting to compile OpenSSL with __stdcall lead to...

C:\libssh\openssl-1.0.1e\tmp32\e_os.h(314) : error C2373: '__iob_func' : redefin
ition; different type modifiers
        C:\Program Files (x86)\Microsoft Visual Studio 10.0\VC\INCLUDE\stdio.h(1
29) : see declaration of '__iob_func'

Like I said before, this is not an area of expertise for me, so I might be missing something that someone who works with C more than once a decade would understand.

Another thing I noticed was that in addition to compiling SSH support, src/transport.c in libgit2 will need to be patched, as right now even if you have the GIT_SSH compiler flag enabled it will still not allow you to use SSH on Windows (see here).

So, I see three main hurdles here:

Even with all this correct, libgit2 would need to be patched to allow for SSH from Windows. I doubt this is a big deal, but something that would have to be done.
I cannot seem to compile OpenSSL with the __stdcall calling convention. This could be overcome by some other solution that doesn't require me changing the calling convention on OpenSSL and libssh2 to __stdcall, perhaps I'm just being C-illiterate here.
There isn't an easy way to build libssh2 with a modern Visual Studio install without first converting the .dsp project. There are a few potential solutions to this, but none that I know of that would be as easy as a script that says "point me to the libssh2 source directory and I'll do all the work".

Unless I can get pointed in the right direction, I'm probably going to stop work on this. The Windows Cryptography Patch for libssh2 makes all of this moot at the cost of not working on XP/Windows Server 2003 and lower, but it would be better than nothing and probably easier to build.

Description

Metadata

Metadata

Assignees

Labels

Type

Projects

Milestone

Relationships

Development

Issue actions