1 files changed, 95 insertions, 7 deletions
diff --git a/src/mds-base.h b/src/mds-base.h
index b4e4ad7..28d7432 100644
--- a/src/mds-base.h
+++ b/src/mds-base.h
@@ -20,6 +20,11 @@
 
 
 #include <pthread.h>
+#include <signal.h>
+
+
+#define MDS_BASE_VARS_VERSION  0
+
 
 
 /**
@@ -30,9 +35,15 @@ typedef struct server_characteristics
   /**
    * Setting this to zero will cause the server to drop privileges as a security precaution
    */
-  int require_privileges;
+  int require_privileges : 1;
   
-} server_characteristics_t;
+  /**
+   * Setting this to non-zero will cause the server to connect to the display
+   */
+  int require_display : 1;
+  
+} __attribute__((packed)) server_characteristics_t;
+
 
 
 /**
@@ -67,17 +78,28 @@ extern int is_respawn;
  */
 extern int is_reexec;
 
+/**
+ * The thread that runs the master loop
+ */
+extern pthread_t master_thread;
+
 
 /**
- * The file descriptor of the socket
- * that is connected to the server
+ * Whether the server has been signaled to terminate
  */
-extern int socket_fd;
+extern volatile sig_atomic_t terminating;
 
 /**
- * The thread that runs the master loop
+ * Whether the server has been signaled to re-exec
  */
-extern pthread_t master_thread;
+extern volatile sig_atomic_t reexecing;
+
+
+/**
+ * The file descriptor of the socket
+ * that is connected to the server
+ */
+extern int socket_fd;
 
 
 
@@ -95,6 +117,8 @@ int trap_signals(void);
  * This function is called when a signal that
  * signals the server to re-exec has been received
  * 
+ * When this function is invoked, it should set `reexecing` to a non-zero value
+ * 
  * @param  signo  The signal that has been received
  */
 extern void received_reexec(int signo);
@@ -105,10 +129,74 @@ extern void received_reexec(int signo);
  * This function is called when a signal that
  * signals the server to re-exec has been received
  * 
+ * When this function is invoked, it should set `terminating` to a non-zero value
+ * 
  * @param  signo  The signal that has been received
  */
 extern void received_terminate(int signo);
 
+/**
+ * This function should be implemented by the actual server implementation
+ * 
+ * This function should initialise the server,
+ * and it not invoked after a re-exec.
+ * 
+ * @return  Non-zero on error
+ */
+extern int initialise_server(void);
+
+/**
+ * This function should be implemented by the actual server implementation
+ * 
+ * Unmarshal server implementation specific data and update the servers state accordingly
+ * 
+ * @param   state_buf  The marshalled data that as not been read already
+ * @return             Non-zero on error
+ */
+extern int unmarshal_server(char* state_buf);
+
+/**
+ * This function should be implemented by the actual server implementation
+ * 
+ * Marshal server implementation specific data into a buffer
+ * 
+ * @param   state_buf  The buffer for the marshalled data
+ * @return             Non-zero on error
+ */
+extern int marshal_server(char* state_buf);
+
+/**
+ * This function should be implemented by the actual server implementation
+ * 
+ * Calculate the number of bytes that will be stored by `marshal_server`
+ * 
+ * On failure the program should `abort()` or exit by other means.
+ * However it should not be possible for this function to fail.
+ * 
+ * @return  The number of bytes that will be stored by `marshal_server`
+ */
+extern size_t marshal_server_size(void);
+
+/**
+ * This function should be implemented by the actual server implementation
+ * 
+ * Attempt to recover from an re-exec failure that has been
+ * detected after the server successfully updated it execution image
+ * 
+ * @return  Non-zero on error
+ */
+extern int reexec_failure_recover(void);
+
+
+/**
+ * This function should be implemented by the actual server implementation
+ * 
+ * Perform the server's mission
+ * 
+ * @return  Non-zero on error
+ */
+extern int master_loop(void);
+
 
 #endif