specify the control-spec's 'signal' command

svn:r3169

doc/control-spec.txt

@@ -72,8 +72,9 @@ the message.
                [The client tried to set a configuration option to an
                 incorrect, ill-formed, or impossible value.]
 
-        0x0006 Unrecognized event code
-               [The client tried to set an event code that we don't recognize.]
+        0x0006 Unrecognized byte code
+               [The client tried to set an byte code in the body that
+                we don't recognize.]
 
         0x0007 Unauthorized.
                [The client tried to send a command that requires
@@ -195,6 +196,22 @@ the message.
   its config options into its torrc. Server returns DONE if successful, or
   ERROR if it can't write the file or some other error occurs.
 
+3.10. SIGNAL (Type 0x0009)
+
+  Sent from the client to the server. The body contains one byte that
+  indicates the action the client wishes the server to take.
+
+      0x01 -- Reload: reload config items, refetch directory.
+      0x02 -- Controlled shutdown: if server is an OP, exit immediately.
+              If it's an OR, close listeners and exit after 30 seconds.
+      0x10 -- Dump stats: log information about open connections and
+              circuits.
+      0x12 -- Debug: switch all open logs to loglevel debug.
+      0x15 -- Immediate shutdown: clean up and exit now.
+
+  The server responds with DONE if the signal is recognized (or simply
+  closes the socket if it was asked to close immediately), else ERROR.
+
 4. Implementation notes
 
 4.1. There are four ways we could authenticate, for now: