Add script to generate save files with custom keys

Allow users to play with keys generated outside Tox core without
depending on features from any specific client. Just generate a
stub save file that every client will understand.

other/fun/make-funny-savefile.py

@@ -0,0 +1,122 @@
+#!/usr/bin/python
+
+"""
+Generate a new (and empty) save file with predefined keys. Used to play
+with externally generated keys.
+
+(c) 2015 Alexandre Erwin Ittner
+
+Distributed under the GNU GPL v3 or later, WITHOUT ANY WARRANTY. See the
+file "COPYING" for license information.
+
+
+Usage:
+
+  ./make-funny-savefile.py <public key> <private key> <user name> <out file>
+
+  The new user profile will be saved to <out file>.
+
+  The keys must be an hex-encoded valid key pair generated by any means
+  (eg. strkey.c); username may be anything. A random nospam value will be
+  generated.
+
+  Once the savefile is done, load it in your favorite client to get some
+  DHT nodes, set status and status messages, add friends, etc.
+
+
+Example (of course, do not try using this key for anything real):
+
+  ./make-funny-savefile.py 123411DC8B1A4760B648E0C7243B65F01069E4858F45C612CE1A6F673B603830 CC39440CFC063E4A95B7F2FB2580210558BE5C073AFC1C9604D431CCA3132238 "Test user" test.tox
+
+
+"""
+
+
+PUBLIC_KEY_LENGTH = 32
+PRIVATE_KEY_LENGTH = 32
+
+# Constants taken from messenger.c
+MESSENGER_STATE_COOKIE_GLOBAL       = 0x15ed1b1f
+MESSENGER_STATE_COOKIE_TYPE         = 0x01ce
+MESSENGER_STATE_TYPE_NOSPAMKEYS     = 1
+MESSENGER_STATE_TYPE_DHT            = 2
+MESSENGER_STATE_TYPE_FRIENDS        = 3
+MESSENGER_STATE_TYPE_NAME           = 4
+MESSENGER_STATE_TYPE_STATUSMESSAGE  = 5
+MESSENGER_STATE_TYPE_STATUS         = 6
+MESSENGER_STATE_TYPE_TCP_RELAY      = 10
+MESSENGER_STATE_TYPE_PATH_NODE      = 11
+
+STATUS_MESSAGE = "New user".encode("utf-8")
+
+
+
+import sys
+import struct
+import os
+
+def abort(msg):
+    print(msg)
+    exit(1)
+
+
+
+if len(sys.argv) != 5:
+    abort("Usage: %s <public key> <private key> <user name> <out file>" % (sys.argv[0]))
+
+try:
+    public_key = sys.argv[1].decode("hex")
+except:
+    abort("Bad public key")
+
+try:
+    private_key = sys.argv[2].decode("hex")
+except:
+    abort("Bad private key")
+
+if len(public_key) != PUBLIC_KEY_LENGTH:
+    abort("Public key with wrong length")
+
+if len(private_key) != PRIVATE_KEY_LENGTH:
+    abort("Private key with wrong length")
+
+user_name = sys.argv[3].encode("utf-8")
+
+if len(user_name) > 32:
+    abort("User name too long (for this script, at least)")
+
+out_file_name = sys.argv[4]
+nospam = os.urandom(4)
+
+
+def make_subheader(h_type, h_length):
+    return (
+        struct.pack("<I", h_length) +
+        struct.pack("<H", h_type) +
+        struct.pack("<H", MESSENGER_STATE_COOKIE_TYPE))
+
+data = (
+    # Main header
+    struct.pack("<I", 0) +
+    struct.pack("<I", MESSENGER_STATE_COOKIE_GLOBAL) +
+
+    # Keys
+    make_subheader(MESSENGER_STATE_TYPE_NOSPAMKEYS,
+        len(nospam) + PUBLIC_KEY_LENGTH + PRIVATE_KEY_LENGTH) +
+    nospam + public_key + private_key +
+
+    # Name (not really needed, but helps)
+    make_subheader(MESSENGER_STATE_TYPE_NAME, len(user_name)) +
+    user_name +
+
+    # Status message (not really needed, but helps)
+    make_subheader(MESSENGER_STATE_TYPE_STATUSMESSAGE, len(STATUS_MESSAGE)) +
+    STATUS_MESSAGE
+)
+
+
+try:
+    with open(out_file_name, "wb") as fp:
+        fp.write(data)
+except Exception as e:
+    abort(str(e))