Make service ABI backwards compatible again

commands/service/service.c

@@ -123,6 +123,9 @@ PRIVATE int req_lu_maxtime = DEFAULT_LU_MAXTIME;
 PRIVATE char command[4096];	
 
 /* Arguments for RS to start a new service */
+PRIVATE endpoint_t rss_scheduler;
+PRIVATE unsigned rss_priority;
+PRIVATE unsigned rss_quantum;
 PRIVATE struct rs_start rs_start;
 
 /* An error occurred. Report the problem, print the usage, and exit. 
@@ -567,7 +570,7 @@ PRIVATE void do_scheduler(config_t *cpe)
 		fatal("do_scheduler: scheduler %d out of range at %s:%d",
 			scheduler_val, cpe->file, cpe->line);
 	}
-	rs_start.rss_scheduler= (endpoint_t) scheduler_val;
+	rss_scheduler= (endpoint_t) scheduler_val;
 }
 
 PRIVATE void do_priority(config_t *cpe)
@@ -605,7 +608,7 @@ PRIVATE void do_priority(config_t *cpe)
 		fatal("do_priority: priority %d out of range at %s:%d",
 			priority_val, cpe->file, cpe->line);
 	}
-	rs_start.rss_priority= (unsigned) priority_val;
+	rss_priority= (unsigned) priority_val;
 }
 
 PRIVATE void do_quantum(config_t *cpe)
@@ -643,7 +646,7 @@ PRIVATE void do_quantum(config_t *cpe)
 		fatal("do_quantum: quantum %d out of range at %s:%d",
 			quantum_val, cpe->file, cpe->line);
 	}
-	rs_start.rss_quantum= (unsigned) quantum_val;
+	rss_quantum= (unsigned) quantum_val;
 }
 
 PRIVATE void do_irq(config_t *cpe)
@@ -1217,14 +1220,21 @@ PUBLIC int main(int argc, char **argv)
 	fatal("no passwd file entry for '%s'", SERVICE_LOGIN);
       rs_start.rss_uid= pw->pw_uid;
 
-      rs_start.rss_scheduler= SCHED_PROC_NR;
+      rss_scheduler= SCHED_PROC_NR;
-      rs_start.rss_priority= USER_Q;
+      rss_priority= USER_Q;
-      rs_start.rss_quantum= 200;
+      rss_quantum= 200;
 
       if (req_config) {
 	assert(progname);
 	do_config(progname, req_config);
       }
+      assert(rss_priority < NR_SCHED_QUEUES);
+      assert(rss_quantum > 0);
+      if (rss_nice_encode(&rs_start.rss_nice, rss_scheduler, 
+	rss_priority, rss_quantum) != OK) {
+	fatal("cannot encode scheduling parameters %d, %u, %u",
+		rss_scheduler, rss_priority, rss_quantum);
+      }
 
       if (req_ipc)
       {
@@ -1237,8 +1247,6 @@ PUBLIC int main(int argc, char **argv)
 	      rs_start.rss_ipclen= 0;
       }
 
-      assert(rs_start.rss_priority < NR_SCHED_QUEUES);
-      assert(rs_start.rss_quantum > 0);
       m.RS_CMD_ADDR = (char *) &rs_start;
       break;
   case RS_DOWN:

include/minix/rs.h

@@ -42,9 +42,7 @@ struct rs_start
 	char *rss_cmd;
 	size_t rss_cmdlen;
 	uid_t rss_uid;
-	endpoint_t rss_scheduler;
+	int rss_nice; /* use rss_nice_encode and _decode */
-	unsigned rss_priority;
-	unsigned rss_quantum;
 	int rss_major;
 	int rss_dev_style;
 	long rss_period;
@@ -99,5 +97,9 @@ struct rprocpub {
 };
 
 _PROTOTYPE( int minix_rs_lookup, (const char *name, endpoint_t *value));
+_PROTOTYPE(int rss_nice_encode, (int *nice, endpoint_t scheduler, 
+	unsigned priority, unsigned quantum));
+_PROTOTYPE(int rss_nice_decode, (int nice, endpoint_t *scheduler, 
+	unsigned *priority, unsigned *quantum));
 
 #endif

lib/libc/other/Makefile.inc

@@ -88,6 +88,7 @@ SRCS+=  \
 	realpath.c \
 	rindex.c \
 	rlimit.c \
+	rss_nice.c \
 	setenv.c \
 	setmode.c \
 	settimeofday.c \

lib/libc/other/rss_nice.c

@@ -0,0 +1,88 @@
+#define _SYSTEM 1
+
+#include <assert.h>
+#include <errno.h>
+#include <minix/com.h>
+#include <minix/config.h>
+#include <minix/const.h>
+#include <minix/ipc.h>
+#include <minix/rs.h>
+#include <minix/type.h>
+#include <stdlib.h>
+#include <timers.h>
+#include <unistd.h>	
+
+#include <machine/archtypes.h>
+#include "../../../kernel/priv.h"
+#include "../../../kernel/proc.h"
+
+#define SCHED_BITS	9
+#define PRIO_BITS	8
+#define QUANTUM_BITS	14
+
+#define SCHED_SHIFT	0
+#define PRIO_SHIFT	(SCHED_BITS + SCHED_SHIFT)
+#define QUANTUM_SHIFT	(PRIO_SHIFT + PRIO_BITS)
+#define ABI_SHIFT	(QUANTUM_SHIFT + QUANTUM_BITS)
+
+#define MAXU(bits)	((unsigned) ((1 << (bits)) - 1))
+#define MINS(bits)	((int) (-(1 << ((bits) - 1))))
+#define MAXS(bits)	((int) ((1 << ((bits) - 1)) - 1))
+
+#define ENCODE(value, shift, bits) \
+	((((unsigned) (value)) & ((1 << (bits)) - 1)) << (shift))
+#define DECODE(value, shift, bits) \
+	((((unsigned) (value)) >> (shift)) & ((1 << (bits)) - 1))
+
+PUBLIC int rss_nice_encode(int *nice, endpoint_t scheduler, 
+	unsigned priority, unsigned quantum)
+{
+	unsigned scheduler_u;
+	
+	assert(ABI_SHIFT == 31);
+
+	/* check whether values fit */
+	if (!nice) return EINVAL;
+	*nice = 0;
+	scheduler_u = (unsigned) (scheduler + NR_TASKS);
+	if (scheduler_u > MAXU(SCHED_BITS)) return EINVAL;
+	if (priority > MAXU(PRIO_BITS)) return EINVAL;
+	if (quantum > MAXU(QUANTUM_BITS)) return EINVAL;
+	
+	/* encode */
+	*nice = ENCODE(scheduler_u, SCHED_SHIFT, SCHED_BITS) |
+		ENCODE(priority, PRIO_SHIFT, PRIO_BITS) |
+		ENCODE(quantum, QUANTUM_SHIFT, QUANTUM_BITS) |
+		ENCODE(1, ABI_SHIFT, 1);
+		
+	return OK;
+}
+
+PUBLIC int rss_nice_decode(int nice, endpoint_t *scheduler, 
+	unsigned *priority, unsigned *quantum)
+{
+	unsigned scheduler_u;
+	
+	assert(ABI_SHIFT == 31);
+	
+	/* check arguments */
+	if (!scheduler) return EINVAL;
+	if (!priority) return EINVAL;
+	if (!quantum) return EINVAL;
+	
+	/* accept either old or new ABI */
+	if (nice & (1 << ABI_SHIFT)) {
+		/* new ABI, decode */
+		scheduler_u = DECODE(nice, SCHED_SHIFT, SCHED_BITS);
+		*scheduler = (int) scheduler_u - NR_TASKS;
+		*priority = DECODE(nice, PRIO_SHIFT, PRIO_BITS);
+		*quantum = DECODE(nice, QUANTUM_SHIFT, QUANTUM_BITS);
+	} else {
+		/* old ABI, not useful so just take defaults */
+		*scheduler = USER_SCH;
+		*priority = USER_Q;
+		*quantum = USER_QUANTUM;
+	}
+	
+	return OK;
+}

servers/rs/manager.c

@@ -1281,9 +1281,9 @@ endpoint_t source;
   }
   rp->r_uid= rs_start->rss_uid;
 
-  rp->r_scheduler= rs_start->rss_scheduler;
+  s = rss_nice_decode(rs_start->rss_nice, &rp->r_scheduler, 
-  rp->r_priority= rs_start->rss_priority;
+	&rp->r_priority, &rp->r_quantum);
-  rp->r_quantum= rs_start->rss_quantum;
+  if (s != OK) return(s);
 
   if (rs_start->rss_flags & RSS_IPC_VALID)
   {

servers/rs/request.c

@@ -787,22 +787,30 @@ message *m_ptr;
  *===========================================================================*/
 PRIVATE int check_request(struct rs_start *rs_start)
 {
+  int s;
+  endpoint_t rss_scheduler;
+  unsigned rss_priority, rss_quantum;
+  
+  s = rss_nice_decode(rs_start->rss_nice, &rss_scheduler, 
+	&rss_priority, &rss_quantum);
+  if (s != OK) return s;
+
   /* Verify scheduling parameters */
-  if (rs_start->rss_scheduler != KERNEL && 
+  if (rss_scheduler != KERNEL && 
-	(rs_start->rss_scheduler < 0 || 
+	(rss_scheduler < 0 || 
-	rs_start->rss_scheduler > LAST_SPECIAL_PROC_NR)) {
+	rss_scheduler > LAST_SPECIAL_PROC_NR)) {
 	printf("RS: check_request: invalid scheduler %d\n", 
-		rs_start->rss_scheduler);
+		rss_scheduler);
 	return EINVAL;
   }
-  if (rs_start->rss_priority >= NR_SCHED_QUEUES) {
+  if (rss_priority >= NR_SCHED_QUEUES) {
 	printf("RS: check_request: priority %u out of range\n", 
-		rs_start->rss_priority);
+		rss_priority);
 	return EINVAL;
   }
-  if (rs_start->rss_quantum <= 0) {
+  if (rss_quantum <= 0) {
 	printf("RS: check_request: quantum %u out of range\n", 
-		rs_start->rss_quantum);
+		rss_quantum);
 	return EINVAL;
   }