Move the SSHTransport class to its own file, so that we may disable SSH

transport when running on Python <2.4.  SSHTransport uses the new subprocess
class, and so it doesn't work on older versions.

Signed-off-by: Ewan Mellor <ewan@xensource.com>

tools/python/xen/util/SSHTransport.py

@@ -0,0 +1,102 @@
+#============================================================================
+# This library is free software; you can redistribute it and/or
+# modify it under the terms of version 2.1 of the GNU Lesser General Public
+# License as published by the Free Software Foundation.
+#
+# This library is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+# Lesser General Public License for more details.
+#
+# You should have received a copy of the GNU Lesser General Public
+# License along with this library; if not, write to the Free Software
+# Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
+#============================================================================
+# Copyright (C) 2006 Anthony Liguori <aliguori@us.ibm.com>
+# Copyright (C) 2006 XenSource Inc.
+#============================================================================
+
+"""
+XML-RPC SSH transport.
+"""
+
+from xmlrpclib import getparser, Fault
+from subprocess import Popen, PIPE
+from getpass import getuser
+from fcntl import ioctl
+import errno
+import os
+import termios
+
+
+def getHTTPURI(uri):
+    (protocol, rest) = uri.split(':', 1)
+    if not rest.startswith('//'):
+        raise ValueError("Invalid ssh URL '%s'" % uri)
+    rest = rest[2:]
+    user = getuser()
+    path = 'RPC2'
+    if rest.find('@') != -1:
+        (user, rest) = rest.split('@', 1)
+    if rest.find('/') != -1:
+        (host, rest) = rest.split('/', 1)
+        if len(rest) > 0:
+            path = rest
+    else:
+        host = rest
+    transport = SSHTransport(host, user)
+    uri = 'http://%s/%s' % (host, path)
+    return transport, uri
+
+
+class SSHTransport(object):
+    def __init__(self, host, user, askpass=None):
+        self.host = host
+        self.user = user
+        self.askpass = askpass
+        self.ssh = None
+
+    def getssh(self):
+        if self.ssh == None:
+            if self.askpass:
+                f = open('/dev/tty', 'w')
+                try:
+                    os.environ['SSH_ASKPASS'] = self.askpass
+                    ioctl(f.fileno(), termios.TIOCNOTTY)
+                finally:
+                    f.close()
+
+            cmd = ['ssh', '%s@%s' % (self.user, self.host), 'xm serve']
+            try:
+                self.ssh = Popen(cmd, bufsize=0, stdin=PIPE, stdout=PIPE)
+            except OSError, (err, msg):
+                if err == errno.ENOENT:
+                    raise Fault(0, "ssh executable not found!")
+                raise
+        return self.ssh
+
+    def request(self, host, handler, request_body, verbose=0):
+        p, u = getparser()
+        ssh = self.getssh()
+        ssh.stdin.write("""POST /%s HTTP/1.1
+User-Agent: Xen
+Host: %s
+Content-Type: text/xml
+Content-Length: %d
+
+%s""" % (handler, host, len(request_body), request_body))
+        ssh.stdin.flush()
+
+        content_length = 0
+        line = ssh.stdout.readline()
+        if line.split()[1] != '200':
+            raise Fault(0, 'Server returned %s' % (' '.join(line[1:])))
+        
+        while line not in ['', '\r\n', '\n']:
+            if line.lower().startswith('content-length:'):
+                content_length = int(line[15:].strip())
+            line = ssh.stdout.readline()
+        content = ssh.stdout.read(content_length)
+        p.feed(content)
+        p.close()
+        return u.close()

tools/python/xen/util/xmlrpclib2.py

@@ -13,7 +13,7 @@
 # Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
 #============================================================================
 # Copyright (C) 2006 Anthony Liguori <aliguori@us.ibm.com>
-# Copyright (C) 2006 XenSource Ltd.
+# Copyright (C) 2006 XenSource Inc.
 #============================================================================
 
 """
@@ -24,67 +24,20 @@ import string
 import types
 
 from httplib import HTTPConnection, HTTP
-from xmlrpclib import Transport, getparser, Fault
+from xmlrpclib import Transport
 from SimpleXMLRPCServer import SimpleXMLRPCServer, SimpleXMLRPCRequestHandler
-from subprocess import Popen, PIPE
-from getpass import getuser
-from fcntl import ioctl
-import xmlrpclib, socket, os, stat, termios, errno
 import SocketServer
+import xmlrpclib, socket, os, stat
 
 from xen.xend.XendLogging import log
 
-class SSHTransport(object):
-    def __init__(self, host, user, askpass=None):
-        self.host = host
-        self.user = user
-        self.askpass = askpass
-        self.ssh = None
-
-    def getssh(self):
-        if self.ssh == None:
-            if self.askpass:
-                f = open('/dev/tty', 'w')
-                try:
-                    os.environ['SSH_ASKPASS'] = self.askpass
-                    ioctl(f.fileno(), termios.TIOCNOTTY)
-                finally:
-                    f.close()
-
-            cmd = ['ssh', '%s@%s' % (self.user, self.host), 'xm serve']
-            try:
-                self.ssh = Popen(cmd, bufsize=0, stdin=PIPE, stdout=PIPE)
-            except OSError, (err, msg):
-                if err == errno.ENOENT:
-                    raise Fault(0, "ssh executable not found!")
-                raise
-        return self.ssh
-
-    def request(self, host, handler, request_body, verbose=0):
-        p, u = getparser()
-        ssh = self.getssh()
-        ssh.stdin.write("""POST /%s HTTP/1.1
-User-Agent: Xen
-Host: %s
-Content-Type: text/xml
-Content-Length: %d
-
-%s""" % (handler, host, len(request_body), request_body))
-        ssh.stdin.flush()
-
-        content_length = 0
-        line = ssh.stdout.readline()
-        if line.split()[1] != '200':
-            raise Fault(0, 'Server returned %s' % (' '.join(line[1:])))
-        
-        while line not in ['', '\r\n', '\n']:
-            if line.lower().startswith('content-length:'):
-                content_length = int(line[15:].strip())
-            line = ssh.stdout.readline()
-        content = ssh.stdout.read(content_length)
-        p.feed(content)
-        p.close()
-        return u.close()
+try:
+    import SSHTransport
+    ssh_enabled = True
+except ImportError:
+    # SSHTransport is disabled on Python <2.4, because it uses the subprocess
+    # package.
+    ssh_enabled = False
 
 
 # A new ServerProxy that also supports httpu urls.  An http URL comes in the
@@ -155,21 +108,12 @@ class ServerProxy(xmlrpclib.ServerProxy):
                 uri = 'http:' + rest
                 transport = UnixTransport()
             elif protocol == 'ssh':
-                if not rest.startswith('//'):
-                    raise ValueError("Invalid ssh URL '%s'" % uri)
-                rest = rest[2:]
-                user = getuser()
-                path = 'RPC2'
-                if rest.find('@') != -1:
-                    (user, rest) = rest.split('@', 1)
-                if rest.find('/') != -1:
-                    (host, rest) = rest.split('/', 1)
-                    if len(rest) > 0:
-                        path = rest
+                global ssh_enabled
+                if ssh_enabled:
+                    (transport, uri) = SSHTransport.getHTTPURI(uri)
                 else:
-                    host = rest
-                transport = SSHTransport(host, user)
-                uri = 'http://%s/%s' % (host, path)
+                    raise ValueError(
+                        "SSH transport not supported on Python <2.4.")
         xmlrpclib.ServerProxy.__init__(self, uri, transport, encoding,
                                        verbose, allow_none)
 

tools/python/xen/xend/XendClient.py

@@ -19,6 +19,7 @@
 
 from xen.util.xmlrpclib2 import ServerProxy
 import os
+import sys
 
 XML_RPC_SOCKET = "/var/run/xend/xmlrpc.sock"
 
@@ -30,4 +31,9 @@ uri = 'httpu:///var/run/xend/xmlrpc.sock'
 if os.environ.has_key('XM_SERVER'):
     uri = os.environ['XM_SERVER']
 
-server = ServerProxy(uri)
+try:
+    server = ServerProxy(uri)
+except ValueError, exn:
+    print >>sys.stderr, exn
+    sys.exit(1)
+