wait.c 5.3 KB
Newer Older
unknown's avatar
unknown committed
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159
/* ==== wait.c ============================================================
 * Copyright (c) 1994 by Chris Provenzano, proven@mit.edu
 * All rights reserved.
 *
 * 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 Chris Provenzano.
 * 4. The name of Chris Provenzano may not be used to endorse or promote 
 *	  products derived from this software without specific prior written
 *	  permission.
 *
 * THIS SOFTWARE IS PROVIDED BY CHRIS PROVENZANO ``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 CHRIS PROVENZANO 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.
 *
 * Description : All the appropriate wait routines.
 *
 *  1.38 94/06/13 proven
 *      -Started coding this file.
 *
 */

#ifndef lint
static const char rcsid[] = "$Id$";
#endif

#include <pthread.h>
#include <signal.h>
#include <sys/types.h>
#include <sys/time.h>
#include <pthread/posix.h>
#include <sys/compat.h>
#include <sys/wait.h>

/* This is an UGLY hack to get wait to compile, something better is needed. */
/* #define _POSIX_SOURCE
#undef _POSIX_SOURCE
*/

struct pthread_queue wait_queue = { NULL, NULL, NULL };
extern void sig_handler_real();

/* ==========================================================================
 * wait_wakeup()
 *
 * This routine is called by the interrupt handler which has locked
 * the current kthread semaphore. Since only threads owned by the 
 * current kthread can be queue here, no additional locks are necessary.
 */
int wait_wakeup()
{
	struct pthread *pthread;
	int ret = 0;

	if (pthread = pthread_queue_deq(& wait_queue)) {
		/* Wakeup all threads, and enqueue them on the run queue */
		do {
			pthread->state = PS_RUNNING;
			if (pthread->pthread_priority > ret) {
				ret = pthread->pthread_priority;
			}
			pthread_prio_queue_enq(pthread_current_prio_queue, pthread);
		} while (pthread = pthread_queue_deq(&wait_queue));
		return(ret);
	}
	return(NOTOK);
}

/* ==========================================================================
 * For the wait calls, it is important that the current kthread is locked
 * before the apropriate wait syscall is preformed. This way we ensure
 * that there is never a case where a thread is waiting for a child but
 * missed the interrupt for that child.
 * Patched by William S. Lear  1997-02-02
 */

/* ==========================================================================
 * waitpid()
 */
pid_t waitpid(pid_t pid, int *status, int options)
{
  pid_t ret;

  pthread_sched_prevent();
  ret = machdep_sys_waitpid(pid, status, options | WNOHANG);
  /* If we are not doing nohang, try again, else return immediately */
  if (!(options & WNOHANG)) {
    while (ret == OK) {
      /* Enqueue thread on wait queue */
      pthread_queue_enq(&wait_queue, pthread_run);

      /* reschedule unlocks scheduler */
      SET_PF_AT_CANCEL_POINT(pthread_run); /* This is a cancel point */
      pthread_resched_resume(PS_WAIT_WAIT);
      CLEAR_PF_AT_CANCEL_POINT(pthread_run); /* No longer at cancel point */

      pthread_sched_prevent();

      ret = machdep_sys_waitpid(pid, status, options | WNOHANG);
    }
  }
  pthread_sched_resume();
  return(ret);
}

/* ==========================================================================
 * wait3()
 * Patched by Monty 1997-02-02
 */
pid_t wait3(__WAIT_STATUS status, int options, void * rusage)
{
  semaphore * lock;
  pid_t ret;

  pthread_sched_prevent();
  ret = machdep_sys_wait3(status, options | WNOHANG, rusage);
  /* If we are not doing nohang, try again, else return immediately */
  if (!(options & WNOHANG)) {
    while (ret == OK) {
      /* Enqueue thread on wait queue */
      pthread_queue_enq(&wait_queue, pthread_run);

      /* reschedule unlocks scheduler */
      SET_PF_AT_CANCEL_POINT(pthread_run); /* This is a cancel point */
      pthread_resched_resume(PS_WAIT_WAIT);
      CLEAR_PF_AT_CANCEL_POINT(pthread_run); /* No longer at cancel point */

      pthread_sched_prevent();

      machdep_sys_wait3(status, options | WNOHANG, rusage);
    }
  }
  pthread_sched_resume();
  return(ret);
}

/* ==========================================================================
 * wait()
 */
pid_t wait(__WAIT_STATUS status)
{
	return(waitpid((pid_t)-1, (int *)status, 0));
}