sys/kern/kern_threads.c

   1 /*
   2  *
   3  * Portions of this code was derived from the file kern_fork.c and as such
   4  * is subject to the copyrights below.
   5  *
   6  * Copyright (c) 1982, 1986, 1989, 1991, 1993
   7  *      The Regents of the University of California.  All rights reserved.
   8  * (c) UNIX System Laboratories, Inc.
   9  * All or some portions of this file are derived from material licensed
  10  * to the University of California by American Telephone and Telegraph
  11  * Co. or Unix System Laboratories, Inc. and are reproduced herein with
  12  * the permission of UNIX System Laboratories, Inc.
  13  *
  14  * Redistribution and use in source and binary forms, with or without
  15  * modification, are permitted provided that the following conditions
  16  * are met:
  17  * 1. Redistributions of source code must retain the above copyright
  18  *    notice, this list of conditions and the following disclaimer.
  19  * 2. Redistributions in binary form must reproduce the above copyright
  20  *    notice, this list of conditions and the following disclaimer in the
  21  *    documentation and/or other materials provided with the distribution.
  22  * 3. All advertising materials mentioning features or use of this software
  23  *    must display the following acknowledgement:
  24  *      This product includes software developed by the University of
  25  *      California, Berkeley and its contributors.
  26  * 4. Neither the name of the University nor the names of its contributors
  27  *    may be used to endorse or promote products derived from this software
  28  *    without specific prior written permission.
  29  *
  30  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
  31  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  32  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  33  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
  34  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  35  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  36  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  37  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  38  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  39  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  40  * SUCH DAMAGE.
  41  *
  42  * Copyright (c) 1996 Douglas Santry
  43  *
  44  * This code is subject to the beer copyright.  If I chance to meet you in a
  45  * bar and this code helped you in some way, you owe me a beer.  Only
  46  * in Germany will I accept domestic beer.  This code may or may not work
  47  * and I certainly make no claims as to its fitness for *any* purpose.
  48  *
  49  * $FreeBSD: src/sys/kern/kern_threads.c,v 1.15 1999/08/28 00:46:15 peter Exp $
  50  * $DragonFly: src/sys/kern/kern_threads.c,v 1.8 2004/01/07 11:04:18 dillon Exp $
  51  */
  52
  53 #include <sys/param.h>
  54 #include <sys/systm.h>
  55 #include <sys/kernel.h>
  56 #include <sys/proc.h>
  57 #include <sys/resourcevar.h>
  58 #include <sys/sysproto.h>
  59 #include <sys/uio.h>            /* uio_yield() fixme */
  60
  61 /*
  62  * Low level support for sleep/wakeup paradigm
  63  * If a timeout is specified:
  64  *      returns 0 if wakeup
  65  *      returns EAGAIN if timed out
  66  *      returns EINVAL if error
  67  *
  68  * If a timeout is not specified:
  69  *
  70  *      returns time waiting in ticks.
  71  */
  72 int
  73 thr_sleep(struct thr_sleep_args *uap)
  74 {
  75         struct proc *p = curproc;
  76         int sleepstart;
  77         struct timespec ts;
  78         struct timeval atv;
  79         int error, timo;
  80
  81         timo = 0;
  82         if (uap->timeout != 0) {
  83                 /*
  84                  * Get timespec struct
  85                  */
  86                 if ((error = copyin(uap->timeout, &ts, sizeof(ts))) != 0) {
  87                         p->p_wakeup = 0;
  88                         return error;
  89                 }
  90                 if (ts.tv_nsec < 0 || ts.tv_nsec >= 1000000000) {
  91                         p->p_wakeup = 0;
  92                         return (EINVAL);
  93                 }
  94                 TIMESPEC_TO_TIMEVAL(&atv, &ts);
  95                 if (itimerfix(&atv)) {
  96                         p->p_wakeup = 0;
  97                         return (EINVAL);
  98                 }
  99                 timo = tvtohz_high(&atv);
 100         }
 101
 102         uap->sysmsg_result = 0;
 103         if (p->p_wakeup == 0) {
 104                 sleepstart = ticks;
 105                 p->p_flag |= P_SINTR;
 106                 error = tsleep(p, 0, "thrslp", timo);
 107                 p->p_flag &= ~P_SINTR;
 108                 if (error == EWOULDBLOCK) {
 109                         p->p_wakeup = 0;
 110                         uap->sysmsg_result = EAGAIN;
 111                         return 0;
 112                 }
 113                 if (uap->timeout == 0)
 114                         uap->sysmsg_result = ticks - sleepstart;
 115         }
 116         p->p_wakeup = 0;
 117         return (0);
 118 }
 119
 120 int
 121 thr_wakeup(struct thr_wakeup_args *uap)
 122 {
 123         struct proc *p = curproc;
 124         struct proc *pSlave = p->p_leader;
 125
 126         while(pSlave && (pSlave->p_pid != uap->pid))
 127                 pSlave = pSlave->p_peers;
 128
 129         if(pSlave == 0) {
 130                 uap->sysmsg_result = ESRCH;
 131                 return(0);
 132         }
 133
 134         pSlave->p_wakeup++;
 135         if((pSlave->p_stat == SSLEEP) && (pSlave->p_wchan == pSlave)) {
 136                 wakeup(pSlave);
 137                 return(0);
 138         }
 139
 140         uap->sysmsg_result = EAGAIN;
 141         return 0;
 142 }
 143
 144 /*
 145  * General purpose yield system call
 146  */
 147 int
 148 yield(struct yield_args *uap)
 149 {
 150         uap->sysmsg_result = 0;
 151         uio_yield();
 152         return(0);
 153 }
 154