[Powerpc-utils-devel] [RFC PATCH] amsvis/amsnet: Replace pickle with json

[Thomas F. <tlf...@li...>]

Due to security concerns, data to be sent over the network
will be serialized via json instead of pickle.  The socket file
interface will also be removed as it did not play nice with the
json load method.  Data transfers will be implemented with the
socket send, sendall, and recv methods.  These implementations along with
json serialization are contained within the functions send_json_message
and receive_json_message, which allow the client and server to transfer
json messages of variable size.

Signed-off-by: Thomas Falcon <tlf...@li...>
---
 scripts/amsvis/powerpcAMS/amsnet.py | 46 ++++++++++++++++++-------------------
 1 file changed, 22 insertions(+), 24 deletions(-)

diff --git a/scripts/amsvis/powerpcAMS/amsnet.py b/scripts/amsvis/powerpcAMS/amsnet.py
index 0e721df..ed460f9 100644
--- a/scripts/amsvis/powerpcAMS/amsnet.py
+++ b/scripts/amsvis/powerpcAMS/amsnet.py
@@ -1,4 +1,4 @@
-"""Network client/server for transmitting pickled data.
+"""Network client/server for transmitting json data.
 """
 
 __author__ = "Robert Jennings rc...@li..."
@@ -8,7 +8,7 @@ __license__ = "Common Public License v1.0"
 import socket
 import types
 import logging
-import cPickle as pickle
+import json
 
 from powerpcAMS.amsdata import gather_all_data, gather_system_data
 
@@ -23,9 +23,22 @@ DATA_METHODS = (gather_all_data, gather_system_data)
 # backwards compatibility is broken.
 CMDVERS = 1.0000000
 
+def send_json_message(socket, message):
+    json_message = json.dumps(message)
+    socket.send("%d\n" % len(json_message))
+    socket.sendall(json_message)
+
+def receive_json_message(socket):
+    len_str = ''
+    while True:
+        c = socket.recv(1)
+        if c == '\n': break
+        len_str += c
+    mesg_len = int(len_str)
+    return json.loads(socket.recv(mesg_len))
 
 def send_data_loop(port):
-    """Send pickled data to any client that connects to a given network port.
+    """Send json data to any client that connects to a given network port.
 
     Keyword arguments:
     port -- network port number to use for this server
@@ -40,7 +53,6 @@ def send_data_loop(port):
         logging.error("Network error: (%d) " % errno + errstr)
         return 1
 
-    sockfile = None
     conn = None
 
     try:
@@ -48,7 +60,6 @@ def send_data_loop(port):
             sock.listen(1)
             (conn, addr) = sock.accept()
             logging.debug("Client connected from " + repr(addr))
-            sockfile = conn.makefile('rwb', 0)
 
             result = "success"
             data = None
@@ -58,7 +69,7 @@ def send_data_loop(port):
             # request data version we can change what the server will
             # send in the future.
             try:
-                client_data = pickle.Unpickler(sockfile).load()
+                client_data = receive_json_message(conn)
             except:
                 logging.debug("Unable to parse client request.")
                 logging.info("Bad client request, ignoring.")
@@ -87,7 +98,7 @@ def send_data_loop(port):
             if result is not "error":
                 data_method = DATA_METHODS[client_data["command"]]
 
-                # Gather system data and send pickled objects to the client
+                # Gather system data and send json objects to the client
                 data = data_method()
                 if data is None:
                     result = "error"
@@ -95,19 +106,14 @@ def send_data_loop(port):
                 logging.debug("Sending %d data objects to client.", len(data))
 
             response = {"result": result, "data": data}
-            sockfile.writelines(pickle.dumps(response, -1))
 
+            send_json_message(conn, response)
             # Clean up
-            sockfile.close()
-            sockfile = None
-
             conn.close()
             conn = None
 
     # Catch a keyboard interrupt by cleaning up the socket
     except KeyboardInterrupt:
-        if sockfile:
-            sockfile.close()
         if conn:
             conn.close()
         sock.close()
@@ -116,8 +122,6 @@ def send_data_loop(port):
 
     # Catch a network error and clean up, return 1 to indicate an error
     except socket.error, msg:
-        if sockfile:
-            sockfile.close()
         if conn:
             conn.close()
         sock.close()
@@ -127,8 +131,6 @@ def send_data_loop(port):
 
     # Give the user something slightly helpful for any other error
     except:
-        if sockfile:
-            sockfile.close()
         if conn:
             conn.close()
         sock.close()
@@ -138,7 +140,7 @@ def send_data_loop(port):
 
 # Client
 def net_get_data(host="localhost", port=50000, cmd=CMD_GET_ALL_DATA):
-    """Get pickled data from a simple network server.
+    """Get json data from a simple network server.
 
     Keywork arguments:
     host -- server host name (default localhost)
@@ -161,8 +163,6 @@ def net_get_data(host="localhost", port=50000, cmd=CMD_GET_ALL_DATA):
             "data": "Client: Is the server still running?",
         }
 
-    sockfile = sock.makefile('rwb', 0) # read/write, unbuffered
-
     # By sending a request to the server, including a version for the data
     # request, we can change the data sent by the server in the future.
     if type(cmd) is types.IntType and cmd >= 0 and cmd <= CMD_MAX:
@@ -179,15 +179,13 @@ def net_get_data(host="localhost", port=50000, cmd=CMD_GET_ALL_DATA):
             "data": "Client: Bad request.",
         }
 
-    sockfile.writelines(pickle.dumps(client_request, -1))
+    send_json_message(sock, client_request)
 
     # Get server response
-    pickler = pickle.Unpickler(sockfile)
     try:
-        data = pickler.load()
+        data = receive_json_message(sock)
     except EOFError:
         pass
-    sockfile.close()
     sock.close()
 
     if type(data) is not types.DictType or "result" not in data:
-- 
1.8.5.2