Initial revision

token.w

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+\subsection{Token Management}
+In SICS any client can issue commands to the SICS server. This
+is a potential cause for trouble with users issuing conflicting
+commands without knowing. In order to deal with this problem a
+token mechanism has been developed. A connection can grab a
+token and then has full control over the SICS server. Any other
+connection will not be priviledged to do anything useful, except
+looking at things. A token can be released manually with a
+special command or is automatically released when the connection
+dies. Another command exists which allows a SICS manager to
+force his way into the SICS server.
+
+This token scheme is implemented using the signal system of the
+task management facility and the connection object. The connection
+object has a field called iGrap which is true if the connection is the
+ultimate and only control connection. This field will be modified
+either directly through commands or via the signal system of the SICS
+task manager. This must be so as all connections need to be notified
+if one connection has grabbed control. 
+
+This object implements the user interface to the token system.
+It checks privileges and issues the necessary signals. No own
+data structure is needed. Just a wrapper function is
+implemented.
+
+@o token.h @{
+/*---------------------------------------------------------------
+                    S I C S  T O K E N
+                    
+   This is the header file for the SICS token management
+   functions. It implements the token command.
+   
+   Mark Koenencke, January 1998
+   
+   copyright: see copyright.h
+   
+----------------------------------------------------------------*/
+#ifndef SICSTOKEN
+#define SICSTOKEN
+  int TokenInit(SConnection *pCon, SicsInterp *pSics, 
+                void *pData, int argc, char *argv[]);
+  /*
+      The Token Factory function.
+  */                  
+  int TokenWrapper(SConnection *pCon, SicsInterp *pSics, 
+                void *pData, int argc, char *argv[]);
+    
+   /* 
+   The wrapper function for the token command.
+   */               
+   
+   int TokenGrabActive(void);
+   /*
+      Returns 1, if a token grab is active, else 0
+   */  
+   
+   void TokenRelease(void);
+   /* 
+     Releases a Token Grab
+   */   
+#endif                       
+@}
+ 
+The functions are:
+\begin{description}
+\item[TokenInit] is the installation routine which configures the
+token system into SICS. Called from the initialisation script.
+\item[TokenWrapper] is the interpreter interface function for the
+token system. Implements the active run time commands.
+\item[TokenGrapActive] returns true (1) if a connection has grabbed
+control or false (0) otherwise.
+\item[TokenRelease] releases the current control token.   
+\end{description}
+