Use 'openssl' executable if pyOpenSSL is not available.

We can't depend on pyOpenSSL because SlapOS is not ready for that.

setup.py

@@ -32,7 +32,7 @@ setup(
     keywords="slapos networkcache shadir shacache",
     install_requires=[
       'setuptools', # for namespace
-      'pyOpenSSL',
+      #'pyOpenSSL',
     ] + additional_install_requires,
     classifiers=[
       'Development Status :: 4 - Beta',

slapos/crypto.py

+# Compatibily code in case that pyOpenSSL is not installed.
+
+import functools, tempfile
+from subprocess import Popen, PIPE, STDOUT
+
+_tmpfile = functools.partial(tempfile.NamedTemporaryFile, prefix=__name__+'-')
+
+class Error(Exception): pass
+
+FILETYPE_PEM = 1
+
+def load_privatekey(type, buffer):
+  r = _tmpfile()
+  r.write(buffer)
+  r.flush()
+  return r
+
+def load_certificate(type, buffer):
+  # extract public key since we only use it to verify signatures
+  r = _tmpfile()
+  p = Popen(("openssl", "x509", "-pubkey", "-noout"),
+            stdin=PIPE, stdout=r, stderr=PIPE)
+  err = p.communicate(buffer)[1]
+  if p.poll():
+    raise Error(err)
+  return r
+
+def sign(pkey, data, digest):
+  p = Popen(("openssl", digest, "-sign", pkey.name),
+            stdin=PIPE, stdout=PIPE, stderr=PIPE)
+  out, err = p.communicate(data)
+  if p.poll():
+    raise Error(err)
+  return out
+
+def verify(cert, signature, data, digest):
+  with _tmpfile() as f:
+    f.write(signature)
+    f.flush()
+    p = Popen(("openssl", digest, "-verify", cert.name, "-signature", f.name),
+              stdin=PIPE, stdout=PIPE, stderr=STDOUT)
+    err = p.communicate(data)[0]
+  if p.poll():
+    raise Error(err)

slapos/libnetworkcache.py

@@ -26,7 +26,10 @@ import tempfile
 import traceback
 import urllib2
 import urlparse
-from OpenSSL import crypto
+try:
+  from OpenSSL import crypto
+except ImportError:
+  from . import crypto
 
 # Timeout here is about timeout to CONNECT to the server (socket initialization then server answers actual data), not to retrieve/send informations.
 # To be clear: it is NOT about uploading/downloading data, but about time to connect to the server, then time that server takes to start answering.