301 lines
7.1 KiB
C
301 lines
7.1 KiB
C
/*
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* Copyright (c) 1997-2004 Erez Zadok
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* Copyright (c) 1990 Jan-Simon Pendry
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* Copyright (c) 1990 Imperial College of Science, Technology & Medicine
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* Copyright (c) 1990 The Regents of the University of California.
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* All rights reserved.
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*
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* This code is derived from software contributed to Berkeley by
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* Jan-Simon Pendry at Imperial College, London.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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* 3. All advertising materials mentioning features or use of this software
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* must display the following acknowledgment:
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* This product includes software developed by the University of
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* California, Berkeley and its contributors.
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* 4. Neither the name of the University nor the names of its contributors
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* may be used to endorse or promote products derived from this software
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* without specific prior written permission.
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*
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* THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
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* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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* ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
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* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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* SUCH DAMAGE.
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*
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* %W% (Berkeley) %G%
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*
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* $Id: sched.c,v 1.4.2.5 2004/01/06 03:15:16 ezk Exp $
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*
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*/
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/*
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* Process scheduler
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*/
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#ifdef HAVE_CONFIG_H
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# include <config.h>
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#endif /* HAVE_CONFIG_H */
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#include <am_defs.h>
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#include <amd.h>
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typedef struct pjob pjob;
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struct pjob {
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qelem hdr; /* Linked list */
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int pid; /* Process ID of job */
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cb_fun cb_fun; /* Callback function */
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voidp cb_closure; /* Closure for callback */
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int w; /* everyone these days uses int, not a "union wait" */
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voidp wchan; /* Wait channel */
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};
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/* globals */
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qelem proc_list_head = {&proc_list_head, &proc_list_head};
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qelem proc_wait_list = {&proc_wait_list, &proc_wait_list};
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int task_notify_todo;
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void
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ins_que(qelem *elem, qelem *pred)
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{
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qelem *p = pred->q_forw;
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elem->q_back = pred;
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elem->q_forw = p;
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pred->q_forw = elem;
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p->q_back = elem;
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}
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void
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rem_que(qelem *elem)
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{
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qelem *p = elem->q_forw;
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qelem *p2 = elem->q_back;
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p2->q_forw = p;
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p->q_back = p2;
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}
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static pjob *
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sched_job(cb_fun cf, voidp ca)
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{
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pjob *p = ALLOC(struct pjob);
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p->cb_fun = cf;
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p->cb_closure = ca;
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/*
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* Now place on wait queue
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*/
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ins_que(&p->hdr, &proc_wait_list);
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return p;
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}
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/*
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* tf: The task to execute (ta is its arguments)
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* cf: Continuation function (ca is its arguments)
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*/
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void
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run_task(task_fun tf, voidp ta, cb_fun cf, voidp ca)
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{
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pjob *p = sched_job(cf, ca);
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#ifdef HAVE_SIGACTION
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sigset_t new, mask;
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#else /* not HAVE_SIGACTION */
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int mask;
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#endif /* not HAVE_SIGACTION */
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p->wchan = (voidp) p;
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#ifdef HAVE_SIGACTION
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sigemptyset(&new); /* initialize signal set we wish to block */
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sigaddset(&new, SIGCHLD); /* only block on SIGCHLD */
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sigprocmask(SIG_BLOCK, &new, &mask);
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#else /* not HAVE_SIGACTION */
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mask = sigblock(sigmask(SIGCHLD));
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#endif /* not HAVE_SIGACTION */
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if ((p->pid = background())) {
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#ifdef HAVE_SIGACTION
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sigprocmask(SIG_SETMASK, &mask, NULL);
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#else /* not HAVE_SIGACTION */
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sigsetmask(mask);
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#endif /* not HAVE_SIGACTION */
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return;
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}
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/* child code runs here, parent have returned to caller */
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exit((*tf) (ta));
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/* firewall... */
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abort();
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}
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/*
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* Schedule a task to be run when woken up
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*/
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void
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sched_task(cb_fun cf, voidp ca, voidp wchan)
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{
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/*
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* Allocate a new task
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*/
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pjob *p = sched_job(cf, ca);
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#ifdef DEBUG
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dlog("SLEEP on %#lx", (unsigned long) wchan);
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#endif /* DEBUG */
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p->wchan = wchan;
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p->pid = 0;
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memset((voidp) &p->w, 0, sizeof(p->w));
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}
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static void
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wakeupjob(pjob *p)
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{
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rem_que(&p->hdr);
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ins_que(&p->hdr, &proc_list_head);
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task_notify_todo++;
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}
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void
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wakeup(voidp wchan)
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{
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pjob *p, *p2;
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if (!foreground)
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return;
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/*
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* Can't user ITER() here because
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* wakeupjob() juggles the list.
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*/
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for (p = AM_FIRST(pjob, &proc_wait_list);
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p2 = NEXT(pjob, p), p != HEAD(pjob, &proc_wait_list);
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p = p2) {
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if (p->wchan == wchan) {
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wakeupjob(p);
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}
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}
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}
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void
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wakeup_task(int rc, int term, voidp cl)
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{
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wakeup(cl);
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}
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/*
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* Run any pending tasks.
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* This must be called with SIGCHLD disabled
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*/
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void
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do_task_notify(void)
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{
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/*
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* Keep taking the first item off the list and processing it.
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*
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* Done this way because the callback can, quite reasonably,
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* queue a new task, so no local reference into the list can be
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* held here.
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*/
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while (AM_FIRST(pjob, &proc_list_head) != HEAD(pjob, &proc_list_head)) {
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pjob *p = AM_FIRST(pjob, &proc_list_head);
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rem_que(&p->hdr);
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/*
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* This job has completed
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*/
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--task_notify_todo;
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/*
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* Do callback if it exists
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*/
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if (p->cb_fun) {
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/* these two trigraphs will ensure compatibility with strict POSIX.1 */
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(*p->cb_fun) (WIFEXITED(p->w) ? WEXITSTATUS(p->w) : 0,
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WIFSIGNALED(p->w) ? WTERMSIG(p->w) : 0,
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p->cb_closure);
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}
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XFREE(p);
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}
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}
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RETSIGTYPE
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sigchld(int sig)
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{
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int w; /* everyone these days uses int, not a "union wait" */
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int pid;
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#ifdef HAVE_WAITPID
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while ((pid = waitpid((pid_t) -1, &w, WNOHANG)) > 0) {
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#else /* not HAVE_WAITPID */
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while ((pid = wait3( &w, WNOHANG, (struct rusage *) 0)) > 0) {
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#endif /* not HAVE_WAITPID */
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pjob *p, *p2;
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if (WIFSIGNALED(w))
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plog(XLOG_ERROR, "Process %d exited with signal %d",
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pid, WTERMSIG(w));
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#ifdef DEBUG
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else
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dlog("Process %d exited with status %d",
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pid, WEXITSTATUS(w));
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#endif /* DEBUG */
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for (p = AM_FIRST(pjob, &proc_wait_list);
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p2 = NEXT(pjob, p), p != HEAD(pjob, &proc_wait_list);
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p = p2) {
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if (p->pid == pid) {
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p->w = w;
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wakeupjob(p);
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break;
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}
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} /* end of for loop */
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#ifdef DEBUG
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if (!p)
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dlog("can't locate task block for pid %d", pid);
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#endif /* DEBUG */
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/*
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* Must count down children inside the while loop, otherwise we won't
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* count them all, and NumChild (and later backoff) will be set
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* incorrectly. SH/RUNIT 940519.
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*/
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if (--NumChild < 0)
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NumChild = 0;
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} /* end of "while wait..." loop */
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#ifdef REINSTALL_SIGNAL_HANDLER
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signal(sig, sigchld);
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#endif /* REINSTALL_SIGNAL_HANDLER */
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if (select_intr_valid)
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longjmp(select_intr, sig);
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}
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