Kbd int (#123)

* Change Session.userauth_keyboardinteractive to use callback function
* Added necessary libssh2 structures for kbd interactive.
* Allow embedded server to do keyboard interactive auth
* Updated contribution guide.

Co-authored-by: Red_M <git@red-m.net>

.github/CONTRIBUTING.rst

@@ -201,42 +201,40 @@ install the development requirements first:
 
    pip install -U -r requirements_dev.txt
 
-Test suite is run via ``nosetests``. Simply calling ``nosetests`` in
+Test suite is run via ``pytest``.
+
+Simply calling ``pytest tests`` in
 the Git repository's root directory will run all available tests.
 
-To run an individual test suite, call nosetests on a particular test file.
+To run an individual test suite, call pytest on a particular test file.
 
 .. code-block:: shell
 
-   nosetests tests/test_sftp.py
+   pytest tests/test_sftp.py
 
 The library does not use a logger and does not output anything.
 
-.. code-block:: shell
-  
-   nosetests --nologcapture
-
-To have nosetests fall back to a PDB prompt on uncaught exceptions, call it
+To have pytest fall back to a PDB prompt on uncaught exceptions, call it
 like so:
 
 .. code-block:: shell
 
-   nosetests --pdb
+   pytest --pdb
 
 If using manually set break points, via ``ipdb.set_trace()`` for example,
-call nosetests like so:
+call pytest like so:
 
 .. code-block:: shell
 
-   nosetests -s
+   pytest -s
 
 to be able to fall back to an IPDB prompt.
 
 Running an individual test within a test suite is also possible, for example:
 
 .. code-block:: shell
 
-   nosetests tests/test_sftp.py:SFTPTestCase.test_readdir
+   pytest tests/test_sftp.py::SFTPTestCase::test_readdir
 
 will run the single test ``test_readdir`` in ``test_sftp.py``.
 
@@ -284,8 +282,7 @@ In root directory of repository:
 
 .. code-block:: shell
 
-   pip install sphinx
-   (cd docs; rm -rf _build; make html)
+   (cd docs; make html)
 
 After building succeeds the documentation is available at ``doc/_build/html``.
 
@@ -304,7 +301,7 @@ repository's root directory:
 
 .. code-block:: shell
 
-   nosetests
+   pytest tests
 
 To ensure documentation builds correctly:
 

setup.py

@@ -54,6 +54,7 @@
                      'boundscheck': False,
                      'optimize.use_switch': True,
                      'wraparound': False,
+                     'language_level': 2,
 }
 cython_args = {
     'cython_directives': cython_directives,

ssh2/c_ssh2.pxd

@@ -58,6 +58,13 @@ cdef extern from "libssh2.h" nogil:
         time_t  st_atime
         time_t  st_mtime
         time_t st_ctime
+    ctypedef struct LIBSSH2_USERAUTH_KBDINT_PROMPT:
+        char *text
+        unsigned int length
+        unsigned char echo
+    ctypedef struct LIBSSH2_USERAUTH_KBDINT_RESPONSE:
+        char *text
+        unsigned int length
     ctypedef struct LIBSSH2_SESSION:
         pass
     ctypedef struct LIBSSH2_CHANNEL:
@@ -142,7 +149,7 @@ cdef extern from "libssh2.h" nogil:
                                                  (void *))
     int libssh2_userauth_keyboard_interactive(LIBSSH2_SESSION *session,
                                               const char *username,
-                                              const char *password)
+                                              (void *))
     int libssh2_userauth_publickey_fromfile_ex(LIBSSH2_SESSION *session,
                                                const char *username,
                                                unsigned int username_len,