external/bsd/am-utils/dist/libamu/ualarm.c

   1 /*      $NetBSD$        */
   2
   3 /*
   4  * Copyright (c) 1997-2009 Erez Zadok
   5  * Copyright (c) 1990 Jan-Simon Pendry
   6  * Copyright (c) 1990 Imperial College of Science, Technology & Medicine
   7  * Copyright (c) 1990 The Regents of the University of California.
   8  * All rights reserved.
   9  *
  10  * This code is derived from software contributed to Berkeley by
  11  * Jan-Simon Pendry at Imperial College, London.
  12  *
  13  * Redistribution and use in source and binary forms, with or without
  14  * modification, are permitted provided that the following conditions
  15  * are met:
  16  * 1. Redistributions of source code must retain the above copyright
  17  *    notice, this list of conditions and the following disclaimer.
  18  * 2. Redistributions in binary form must reproduce the above copyright
  19  *    notice, this list of conditions and the following disclaimer in the
  20  *    documentation and/or other materials provided with the distribution.
  21  * 3. All advertising materials mentioning features or use of this software
  22  *    must display the following acknowledgment:
  23  *      This product includes software developed by the University of
  24  *      California, Berkeley and its contributors.
  25  * 4. Neither the name of the University nor the names of its contributors
  26  *    may be used to endorse or promote products derived from this software
  27  *    without specific prior written permission.
  28  *
  29  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
  30  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  31  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  32  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
  33  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  34  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  35  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  36  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  37  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  38  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  39  * SUCH DAMAGE.
  40  *
  41  *
  42  * File: am-utils/libamu/ualarm.c
  43  *
  44  */
  45
  46 #ifdef HAVE_CONFIG_H
  47 # include <config.h>
  48 #endif /* HAVE_CONFIG_H */
  49 #include <am_defs.h>
  50 #include <amu.h>
  51
  52 #define USPS    1000000         /* # of microseconds in a second */
  53
  54
  55 /*
  56  * Generate a SIGALRM signal in ``usecs'' microseconds.
  57  * If ``reload'' is non-zero, keep generating SIGALRM
  58  * every ``reload'' microseconds after the first signal.
  59  */
  60 u_int
  61 ualarm(u_int usecs, u_int interval)
  62 {
  63   struct itimerval new, old;
  64
  65   new.it_interval.tv_usec = interval % USPS;
  66   new.it_interval.tv_sec = interval / USPS;
  67   new.it_value.tv_usec = usecs % USPS;
  68   new.it_value.tv_sec = usecs / USPS;
  69
  70   if (setitimer(ITIMER_REAL, &new, &old) == 0)
  71     return (old.it_value.tv_sec * USPS + old.it_value.tv_usec);
  72
  73   return -1;
  74 }