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 1.12 2007/02/18 16:12:43 corecode 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 /*
  63  * XXX lwp
  64  *
  65  * I am unhappy code, please remove me
  66  */
  67
  68
  69 /*
  70  * Low level support for sleep/wakeup paradigm
  71  * If a timeout is specified:
  72  *      returns 0 if wakeup
  73  *      returns EAGAIN if timed out
  74  *      returns EINVAL if error
  75  *
  76  * If a timeout is not specified:
  77  *
  78  *      returns time waiting in ticks.
  79  */
  80 int
  81 sys_thr_sleep(struct thr_sleep_args *uap)
  82 {
  83         struct proc *p = curproc;
  84         struct lwp *lp = curthread->td_lwp;
  85         int sleepstart;
  86         struct timespec ts;
  87         struct timeval atv;
  88         int error, timo;
  89
  90         timo = 0;
  91         if (uap->timeout != 0) {
  92                 /*
  93                  * Get timespec struct
  94                  */
  95                 if ((error = copyin(uap->timeout, &ts, sizeof(ts))) != 0) {
  96                         p->p_wakeup = 0;
  97                         return error;
  98                 }
  99                 if (ts.tv_nsec < 0 || ts.tv_nsec >= 1000000000) {
 100                         p->p_wakeup = 0;
 101                         return (EINVAL);
 102                 }
 103                 TIMESPEC_TO_TIMEVAL(&atv, &ts);
 104                 if (itimerfix(&atv)) {
 105                         p->p_wakeup = 0;
 106                         return (EINVAL);
 107                 }
 108                 timo = tvtohz_high(&atv);
 109         }
 110
 111         uap->sysmsg_result = 0;
 112         if (p->p_wakeup == 0) {
 113                 sleepstart = ticks;
 114                 lp->lwp_flag |= LWP_SINTR;
 115                 error = tsleep(p, 0, "thrslp", timo);
 116                 lp->lwp_flag &= ~LWP_SINTR;
 117                 if (error == EWOULDBLOCK) {
 118                         p->p_wakeup = 0;
 119                         uap->sysmsg_result = EAGAIN;
 120                         return 0;
 121                 }
 122                 if (uap->timeout == 0)
 123                         uap->sysmsg_result = ticks - sleepstart;
 124         }
 125         p->p_wakeup = 0;
 126         return (0);
 127 }
 128
 129 int
 130 sys_thr_wakeup(struct thr_wakeup_args *uap)
 131 {
 132         struct proc *p = curproc;
 133         struct proc *pSlave = p->p_leader;
 134         struct lwp *lpSlave;
 135
 136         while(pSlave && (pSlave->p_pid != uap->pid))
 137                 pSlave = pSlave->p_peers;
 138
 139         if(pSlave == 0) {
 140                 uap->sysmsg_result = ESRCH;
 141                 return(0);
 142         }
 143
 144         lpSlave = FIRST_LWP_IN_PROC(pSlave);
 145         pSlave->p_wakeup++;
 146         if((lpSlave->lwp_stat == LSSLEEP) && lpSlave->lwp_wchan == pSlave) {
 147                 wakeup(pSlave);
 148                 return(0);
 149         }
 150
 151         uap->sysmsg_result = EAGAIN;
 152         return 0;
 153 }
 154
 155 /*
 156  * General purpose yield system call
 157  */
 158 int
 159 sys_yield(struct yield_args *uap)
 160 {
 161         uap->sysmsg_result = 0;
 162         uio_yield();
 163         return(0);
 164 }
 165