[src/netbsd-1-4]: src/sys/kern Pull up revisions 1.42-1.43 (requested by thor...

[he <he%NetBSD.org@localhost>]

details:   https://anonhg.NetBSD.org/src/rev/ea2c473fd63f
branches:  netbsd-1-4
changeset: 470379:ea2c473fd63f
user:      he <he%NetBSD.org@localhost>
date:      Fri Feb 18 20:25:34 2000 +0000

description:
Pull up revisions 1.42-1.43 (requested by thorpej):
  Implement ratecheck(), a function which can help kernel programmers
  implement rate-limited actions.

diffstat:

 sys/kern/kern_time.c |  67 +++++++++++++++++++++++++++++++++++++++++++++++++++-
 1 files changed, 66 insertions(+), 1 deletions(-)

diffs (78 lines):

diff -r 7b520981113e -r ea2c473fd63f sys/kern/kern_time.c
--- a/sys/kern/kern_time.c      Fri Feb 18 19:40:07 2000 +0000
+++ b/sys/kern/kern_time.c      Fri Feb 18 20:25:34 2000 +0000
@@ -1,4 +1,40 @@
-/*     $NetBSD: kern_time.c,v 1.36.6.2 1999/10/20 23:48:33 he Exp $    */
+/*     $NetBSD: kern_time.c,v 1.36.6.3 2000/02/18 20:25:34 he Exp $    */
+
+/*-
+ * Copyright (c) 2000 The NetBSD Foundation, Inc.
+ * All rights reserved.
+ *
+ * This code is derived from software contributed to The NetBSD Foundation
+ * by Christopher G. Demetriou.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ * 3. All advertising materials mentioning features or use of this software
+ *    must display the following acknowledgement:
+ *     This product includes software developed by the NetBSD
+ *     Foundation, Inc. and its contributors.
+ * 4. Neither the name of The NetBSD Foundation nor the names of its
+ *    contributors may be used to endorse or promote products derived
+ *    from this software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
+ * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
+ * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
+ * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
+ * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
+ * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
+ * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
+ * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
+ * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
+ * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
+ * POSSIBILITY OF SUCH DAMAGE.
+ */
 
 /*
  * Copyright (c) 1982, 1986, 1989, 1993
@@ -591,3 +627,32 @@
                itp->it_value.tv_usec = 0;              /* sec is already 0 */
        return (0);
 }
+
+/*
+ * ratecheck(): simple time-based rate-limit checking.  see ratecheck(9)
+ * for usage and rationale.
+ */
+int
+ratecheck(lasttime, mininterval)
+       struct timeval *lasttime;
+       const struct timeval *mininterval;
+{
+       struct timeval delta;
+       int s, rv = 0;
+
+       s = splclock(); 
+       timersub(&mono_time, lasttime, &delta);
+
+       /*
+        * check for 0,0 is so that the message will be seen at least once,
+        * even if interval is huge.
+        */
+       if (timercmp(&delta, mininterval, >=) ||
+           (lasttime->tv_sec == 0 && lasttime->tv_usec == 0)) {
+               *lasttime = mono_time;
+               rv = 1;
+       }
+       splx(s);
+
+       return (rv);
+}