gen/FreeBSD/ualarm.c

   1 /*-
   2  * SPDX-License-Identifier: BSD-3-Clause
   3  *
   4  * Copyright (c) 1985, 1993
   5  *      The Regents of the University of California.  All rights reserved.
   6  *
   7  * Redistribution and use in source and binary forms, with or without
   8  * modification, are permitted provided that the following conditions
   9  * are met:
  10  * 1. Redistributions of source code must retain the above copyright
  11  *    notice, this list of conditions and the following disclaimer.
  12  * 2. Redistributions in binary form must reproduce the above copyright
  13  *    notice, this list of conditions and the following disclaimer in the
  14  *    documentation and/or other materials provided with the distribution.
  15  * 3. Neither the name of the University nor the names of its contributors
  16  *    may be used to endorse or promote products derived from this software
  17  *    without specific prior written permission.
  18  *
  19  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
  20  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  21  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  22  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
  23  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  24  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  25  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  26  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  27  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  28  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  29  * SUCH DAMAGE.
  30  */
  31
  32 #include <sys/cdefs.h>
  33 #if defined(LIBC_SCCS) && !defined(lint)
  34 __SCCSID("@(#)ualarm.c  8.1 (Berkeley) 6/4/93");
  35 __FBSDID("$FreeBSD$");
  36 #endif /* LIBC_SCCS and not lint */
  37
  38 #include <sys/time.h>
  39 #include <unistd.h>
  40
  41 #define USPS    1000000         /* # of microseconds in a second */
  42
  43 /*
  44  * Generate a SIGALRM signal in ``usecs'' microseconds.
  45  * If ``reload'' is non-zero, keep generating SIGALRM
  46  * every ``reload'' microseconds after the first signal.
  47  */
  48 useconds_t
  49 ualarm(useconds_t usecs, useconds_t reload)
  50 {
  51         struct itimerval new, old;
  52
  53         new.it_interval.tv_usec = reload % USPS;
  54         new.it_interval.tv_sec = reload / USPS;
  55
  56         new.it_value.tv_usec = usecs % USPS;
  57         new.it_value.tv_sec = usecs / USPS;
  58
  59         if (setitimer(ITIMER_REAL, &new, &old) == 0)
  60                 return (old.it_value.tv_sec * USPS + old.it_value.tv_usec);
  61         return (-1);
  62 }