Don't require the remote server to have sshuttle installed.

Instead, grab our source code, send it over the link, and have python eval
it and then start the server.py main() function.

Strangely, there's now *less* horrible stuff in ssh.py, because we no longer
have to munge around with the PATH environment variable.  And this
significantly reduces the setup required to get sshuttle going.

Based on a suggestion from Wayne Scott.

ssh.py

@@ -1,7 +1,20 @@
-import sys, os, re, subprocess, socket
+import sys, os, re, subprocess, socket, zlib
 import helpers
 from helpers import *
 
+
+def readfile(name):
+    basedir = os.path.dirname(os.path.abspath(sys.argv[0]))
+    fullname = os.path.join(basedir, name)
+    return open(fullname, 'rb').read()
+
+
+def empackage(z, filename):
+    content = z.compress(readfile(filename))
+    content += z.flush(zlib.Z_SYNC_FLUSH)
+    return '%s\n%d\n%s' % (filename,len(content), content)
+
+
 def connect(rhostport):
     main_exe = sys.argv[0]
     l = (rhostport or '').split(':', 1)
@@ -9,45 +22,42 @@ def connect(rhostport):
     portl = []
     if len(l) > 1:
         portl = ['-p', str(int(l[1]))]
-    nicedir = os.path.split(os.path.abspath(main_exe))[0]
-    nicedir = re.sub(r':', "_", nicedir)
-    myhome = os.path.expanduser('~') + '/'
-    if nicedir.startswith(myhome):
-        nicedir2 = nicedir[len(myhome):]
-    else:
-        nicedir2 = nicedir
+
     if rhost == '-':
         rhost = None
+
+    z = zlib.compressobj(1)
+    content = readfile('assembler.py')
+    content2 = (empackage(z, 'helpers.py') +
+                empackage(z, 'ssnet.py') +
+                empackage(z, 'server.py') +
+                "\n")
+    
+    pyscript = r"""
+                import sys;
+                skip_imports=1;
+                verbosity=%d;
+                exec compile(sys.stdin.read(%d), "assembler.py", "exec")
+                """ % (helpers.verbose or 0, len(content))
+    pyscript = re.sub(r'\s+', ' ', pyscript.strip())
+
+        
     if not rhost:
-        argv = ['sshuttle', '--server'] + ['-v']*(helpers.verbose or 0)
+        argv = ['python', '-c', pyscript]
     else:
-        # WARNING: shell quoting security holes are possible here, so we
-        # have to be super careful.  We have to use 'sh -c' because
-        # csh-derived shells can't handle PATH= notation.  We can't
-        # set PATH in advance, because ssh probably replaces it.  We
-        # can't exec *safely* using argv, because *both* ssh and 'sh -c'
-        # allow shellquoting.  So we end up having to double-shellquote
-        # stuff here.
-        escapedir  = re.sub(r'([^\w/])', r'\\\\\\\1', nicedir)
-        escapedir2 = re.sub(r'([^\w/])', r'\\\\\\\1', nicedir2)
-        cmd = r"""
-                   sh -c PATH=%s:'$HOME'/%s:'$PATH exec sshuttle --server%s'
-               """ % (escapedir, escapedir2,
-                      ' -v' * (helpers.verbose or 0))
-        argv = ['ssh'] + portl + [rhost, '--', cmd.strip()]
-        debug2('executing: %r\n' % argv)
+        argv = ['ssh'] + portl + [rhost, '--', "python -c '%s'" % pyscript]
     (s1,s2) = socket.socketpair()
     def setup():
         # runs in the child process
         s2.close()
-        if not rhost:
-            os.environ['PATH'] = ':'.join([nicedir,
-                                           os.environ.get('PATH', '')])
         os.setsid()
     s1a,s1b = os.dup(s1.fileno()), os.dup(s1.fileno())
     s1.close()
+    debug2('executing: %r\n' % argv)
     p = subprocess.Popen(argv, stdin=s1a, stdout=s1b, preexec_fn=setup,
                          close_fds=True)
     os.close(s1a)
     os.close(s1b)
+    s2.sendall(content)
+    s2.sendall(content2)
     return p, s2