IPC status code for receive().

IPC changes:
- receive() is changed to take an additional parameter, which is a pointer to
a status code.
- The status code is filled in by the kernel to provide additional information
to the caller. For now, the kernel only fills in the IPC call used by the
sender.

Syslib changes:
- sef_receive() has been split into sef_receive() (with the original semantics)
and sef_receive_status() which exposes the status code to userland.
- Ideally, every sys process should gradually switch to sef_receive_status()
and use is_ipc_notify() as a dependable way to check for notify.
- SEF has been modified to use is_ipc_notify() and demonstrate how to use the
new status code.

lib/libsys/sef.c

@@ -38,7 +38,7 @@ EXTERN _PROTOTYPE( int do_sef_signal_request, (message *m_ptr) );
 PUBLIC void sef_startup()
 {
 /* SEF startup interface for system services. */
-  int r;
+  int r, status;
 
   /* Get information about self. */
   r = sys_whoami(&sef_self_endpoint, sef_self_name, SEF_SELF_NAME_MAXLEN);
@@ -57,7 +57,8 @@ PUBLIC void sef_startup()
   else {
       message m;
 
-      if((r = receive(RS_PROC_NR, &m)) != OK) {
+      r = receive(RS_PROC_NR, &m, &status);
+      if(r != OK) {
           panic("unable to receive from RS: %d", r);
       }
       if(IS_SEF_INIT_REQUEST(&m)) {
@@ -73,12 +74,12 @@ PUBLIC void sef_startup()
 }
 
 /*===========================================================================*
- *				sef_receive				     *
+ *				sef_receive_status			     *
  *===========================================================================*/
-PUBLIC int sef_receive(endpoint_t src, message *m_ptr)
+PUBLIC int sef_receive_status(endpoint_t src, message *m_ptr, int *status_ptr)
 {
 /* SEF receive() interface for system services. */
-  int r;
+  int r, status;
 
   while(TRUE) {
 
@@ -88,14 +89,15 @@ PUBLIC int sef_receive(endpoint_t src, message *m_ptr)
 #endif
 
       /* Receive and return in case of error. */
-      r = receive(src, m_ptr);
+      r = receive(src, m_ptr, &status);
+      if(status_ptr) *status_ptr = status;
       if(r != OK) {
           return r;
       }
 
 #if INTERCEPT_SEF_PING_REQUESTS
       /* Intercept SEF Ping requests. */
-      if(IS_SEF_PING_REQUEST(m_ptr)) {
+      if(IS_SEF_PING_REQUEST(m_ptr, status)) {
           if(do_sef_ping_request(m_ptr) == OK) {
               continue;
           }
@@ -104,7 +106,7 @@ PUBLIC int sef_receive(endpoint_t src, message *m_ptr)
 
 #if INTERCEPT_SEF_LU_REQUESTS
       /* Intercept SEF Live update requests. */
-      if(IS_SEF_LU_REQUEST(m_ptr)) {
+      if(IS_SEF_LU_REQUEST(m_ptr, status)) {
           if(do_sef_lu_request(m_ptr) == OK) {
               continue;
           }
@@ -113,7 +115,7 @@ PUBLIC int sef_receive(endpoint_t src, message *m_ptr)
 
 #if INTERCEPT_SEF_SIGNAL_REQUESTS
       /* Intercept SEF Signal requests. */
-      if(IS_SEF_SIGNAL_REQUEST(m_ptr)) {
+      if(IS_SEF_SIGNAL_REQUEST(m_ptr, status)) {
           if(do_sef_signal_request(m_ptr) == OK) {
               continue;
           }

lib/libsys/tickdelay.c

@@ -23,7 +23,7 @@ long ticks;				/* number of ticks to wait */
     s = _kernel_call(SYS_SETALARM, &m);
     if (s != OK) return(s);
 
-    receive(CLOCK,&m_alarm);		/* await synchronous alarm */
+    sef_receive(CLOCK,&m_alarm);		/* await synchronous alarm */
 
     /* Check if we must reschedule the current alarm. */
     if (m.ALRM_TIME_LEFT > 0 && m.ALRM_TIME_LEFT != TMR_NEVER) {