Rather than interrupting 10 times per second then checking

to see if there's anything to do, schedule the next alarm
based on the next required timeout.
This decreases the load when there are lots of relatively
idle ppp processes.

While I'm in there, handle the possibility that a timeout
makes the timer element go out of scope by grabbing the
enext pointer before executing the timer function.

1 files changed, 42 insertions, 45 deletions

diff --git a/usr.sbin/ppp/timer.c b/usr.sbin/ppp/timer.c
index 9accce3..0bf2258 100644
--- a/usr.sbin/ppp/timer.c
+++ b/usr.sbin/ppp/timer.c
@@ -17,11 +17,12 @@
  * IMPLIED WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED
  * WARRANTIES OF MERCHANTIBILITY AND FITNESS FOR A PARTICULAR PURPOSE.
  *
- * $Id: timer.c,v 1.30 1998/06/20 01:36:38 brian Exp $
+ * $Id: timer.c,v 1.31 1998/06/27 14:18:11 brian Exp $
  *
  *  TODO:
  */
 
+#include <errno.h>
 #include <signal.h>
 #include <stdio.h>
 #include <sys/time.h>
@@ -96,8 +97,8 @@ timer_Start(struct pppTimer * tp)
   if (pt) {
     pt->next = tp;
   } else {
-    timer_InitService();
     TimerList = tp;
+    timer_InitService(0);	/* Start the Timer Service */
   }
   if (t)
     t->rest -= tp->rest;
@@ -143,7 +144,7 @@ StopTimerNoBlock(struct pppTimer * tp)
 static void
 TimerService(void)
 {
-  struct pppTimer *tp, *exp, *wt;
+  struct pppTimer *tp, *exp, *next;
 
   if (log_IsKept(LogTIMER)) {
     static time_t t;		/* Only show timers globally every second */
@@ -153,43 +154,34 @@ TimerService(void)
       timer_Show(LogTIMER, NULL);
     t = n;
   }
+
   tp = TimerList;
   if (tp) {
-    tp->rest--;
-    if (tp->rest == 0) {
-
-      /*
-       * Multiple timers may expires at once. Create list of expired timers.
-       */
-      exp = NULL;
-      do {
-	tp->state = TIMER_EXPIRED;
-	wt = tp->next;
-	tp->enext = exp;
-	exp = tp;
-	tp = wt;
-      } while (tp && (tp->rest == 0));
-
-      TimerList = tp;
-      if (TimerList == NULL)	/* No timers ? */
-	timer_TermService();	/* Terminate Timer Service */
-
-      /*
-       * Process all expired timers.
-       */
-      while (exp) {
-#ifdef notdef
-	timer_Stop(exp);
-#endif
-	if (exp->func)
-	  (*exp->func) (exp->arg);
-
-	/*
-	 * Just Removing each item from expired list And exp->enext will be
-	 * intialized at next expire in this funtion.
-	 */
-	exp = exp->enext;
-      }
+    tp->rest = 0;
+
+    /* Multiple timers might expire at once. Create a list of expired timers */
+    exp = NULL;
+    do {
+      tp->state = TIMER_EXPIRED;
+      next = tp->next;
+      tp->enext = exp;
+      exp = tp;
+      tp = next;
+    } while (tp && tp->rest == 0);
+  
+    TimerList = tp;
+    if (TimerList != NULL)	/* Any timers remaining ? */
+      timer_InitService(1);	/* Restart the Timer Service */
+    else
+      timer_TermService();	/* Stop the Timer Service */
+  
+    /* Process all expired timers */
+    while (exp) {
+      next = exp->enext;
+      exp->enext = NULL;
+      if (exp->func)
+        (*exp->func)(exp->arg);
+      exp = next;
     }
   }
 }
@@ -223,15 +215,20 @@ timer_Show(int LogLevel, struct prompt *prompt)
 }
 
 void 
-timer_InitService()
+timer_InitService(int restart)
 {
   struct itimerval itimer;
 
-  sig_signal(SIGALRM, (void (*) (int)) TimerService);
-  itimer.it_interval.tv_sec = itimer.it_value.tv_sec = 0;
-  itimer.it_interval.tv_usec = itimer.it_value.tv_usec = TICKUNIT;
-  if (setitimer(ITIMER_REAL, &itimer, NULL) == -1)
-    log_Printf(LogERROR, "Unable to set itimer.\n");
+  if (TimerList) {
+    if (!restart)
+      sig_signal(SIGALRM, (void (*)(int))TimerService);
+    itimer.it_interval.tv_sec = 0;
+    itimer.it_interval.tv_usec = 0;
+    itimer.it_value.tv_sec = TimerList->rest / SECTICKS;
+    itimer.it_value.tv_usec = (TimerList->rest % SECTICKS) * TICKUNIT;
+    if (setitimer(ITIMER_REAL, &itimer, NULL) == -1)
+      log_Printf(LogERROR, "Unable to set itimer (%s)\n", sys_errlist[errno]);
+  }
 }
 
 void 
@@ -242,6 +239,6 @@ timer_TermService(void)
   itimer.it_interval.tv_usec = itimer.it_interval.tv_sec = 0;
   itimer.it_value.tv_usec = itimer.it_value.tv_sec = 0;
   if (setitimer(ITIMER_REAL, &itimer, NULL) == -1)
-    log_Printf(LogERROR, "Unable to set itimer.\n");
+    log_Printf(LogERROR, "Unable to set itimer (%s)\n", sys_errlist[errno]);
   sig_signal(SIGALRM, SIG_IGN);
 }