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/*
* Copyright (c) 1997-1998 Erez Zadok
* Copyright (c) 1990 Jan-Simon Pendry
* Copyright (c) 1990 Imperial College of Science, Technology & Medicine
* Copyright (c) 1990 The Regents of the University of California.
* All rights reserved.
*
* This code is derived from software contributed to Berkeley by
* Jan-Simon Pendry at Imperial College, London.
*
* 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 the University of
* California, Berkeley and its contributors.
* 4. Neither the name of the University nor the names of its contributors
* may be used to endorse or promote products derived from this software
* without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``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 THE REGENTS OR CONTRIBUTORS 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.
*
* %W% (Berkeley) %G%
*
* $Id: sched.c,v 5.2.2.1 1992/02/09 15:09:02 jsp beta $
*
*/
/*
* Process scheduler
*/
#ifdef HAVE_CONFIG_H
# include <config.h>
#endif /* HAVE_CONFIG_H */
#include <am_defs.h>
#include <amd.h>
typedef struct pjob pjob;
struct pjob {
qelem hdr; /* Linked list */
int pid; /* Process ID of job */
cb_fun cb_fun; /* Callback function */
voidp cb_closure; /* Closure for callback */
int w; /* everyone these days uses int, not a "union wait" */
voidp wchan; /* Wait channel */
};
/* globals */
qelem proc_list_head = {&proc_list_head, &proc_list_head};
qelem proc_wait_list = {&proc_wait_list, &proc_wait_list};
int task_notify_todo;
void
ins_que(qelem *elem, qelem *pred)
{
qelem *p = pred->q_forw;
elem->q_back = pred;
elem->q_forw = p;
pred->q_forw = elem;
p->q_back = elem;
}
void
rem_que(qelem *elem)
{
qelem *p = elem->q_forw;
qelem *p2 = elem->q_back;
p2->q_forw = p;
p->q_back = p2;
}
static pjob *
sched_job(cb_fun cf, voidp ca)
{
pjob *p = ALLOC(struct pjob);
p->cb_fun = cf;
p->cb_closure = ca;
/*
* Now place on wait queue
*/
ins_que(&p->hdr, &proc_wait_list);
return p;
}
/*
* tf: The task to execute (ta is its arguments)
* cf: Continuation function (ca is its arguments)
*/
void
run_task(task_fun tf, voidp ta, cb_fun cf, voidp ca)
{
pjob *p = sched_job(cf, ca);
#ifdef HAVE_SIGACTION
sigset_t new, mask;
#else /* not HAVE_SIGACTION */
int mask;
#endif /* not HAVE_SIGACTION */
p->wchan = (voidp) p;
#ifdef HAVE_SIGACTION
sigemptyset(&new); /* initialise signal set we wish to block */
sigaddset(&new, SIGCHLD); /* only block on SIGCHLD */
sigprocmask(SIG_BLOCK, &new, &mask);
#else /* not HAVE_SIGACTION */
mask = sigblock(sigmask(SIGCHLD));
#endif /* not HAVE_SIGACTION */
if ((p->pid = background())) {
#ifdef HAVE_SIGACTION
sigprocmask(SIG_SETMASK, &mask, NULL);
#else /* not HAVE_SIGACTION */
sigsetmask(mask);
#endif /* not HAVE_SIGACTION */
return;
}
/* child code runs here, parent have returned to caller */
exit((*tf) (ta));
/* firewall... */
abort();
}
/*
* Schedule a task to be run when woken up
*/
void
sched_task(cb_fun cf, voidp ca, voidp wchan)
{
/*
* Allocate a new task
*/
pjob *p = sched_job(cf, ca);
#ifdef DEBUG
dlog("SLEEP on %#x", wchan);
#endif /* DEBUG */
p->wchan = wchan;
p->pid = 0;
memset((voidp) &p->w, 0, sizeof(p->w));
}
static void
wakeupjob(pjob *p)
{
rem_que(&p->hdr);
ins_que(&p->hdr, &proc_list_head);
task_notify_todo++;
}
void
wakeup(voidp wchan)
{
pjob *p, *p2;
if (!foreground)
return;
/*
* Can't user ITER() here because
* wakeupjob() juggles the list.
*/
for (p = AM_FIRST(pjob, &proc_wait_list);
p2 = NEXT(pjob, p), p != HEAD(pjob, &proc_wait_list);
p = p2) {
if (p->wchan == wchan) {
wakeupjob(p);
}
}
}
void
wakeup_task(int rc, int term, voidp cl)
{
wakeup(cl);
}
/*
* Run any pending tasks.
* This must be called with SIGCHLD disabled
*/
void
do_task_notify(void)
{
/*
* Keep taking the first item off the list and processing it.
*
* Done this way because the the callback can, quite reasonably,
* queue a new task, so no local reference into the list can be
* held here.
*/
while (AM_FIRST(pjob, &proc_list_head) != HEAD(pjob, &proc_list_head)) {
pjob *p = AM_FIRST(pjob, &proc_list_head);
rem_que(&p->hdr);
/*
* This job has completed
*/
--task_notify_todo;
/*
* Do callback if it exists
*/
if (p->cb_fun) {
/* these two trigraphs will ensure compatibity with strict POSIX.1 */
(*p->cb_fun) (WIFEXITED(p->w) ? WEXITSTATUS(p->w) : 0,
WIFSIGNALED(p->w) ? WTERMSIG(p->w) : 0,
p->cb_closure);
}
XFREE(p);
}
}
RETSIGTYPE
sigchld(int sig)
{
int w; /* everyone these days uses int, not a "union wait" */
int pid;
#ifdef HAVE_WAITPID
while ((pid = waitpid((pid_t) -1, &w, WNOHANG)) > 0) {
#else /* not HAVE_WAITPID */
while ((pid = wait3( &w, WNOHANG, (struct rusage *) 0)) > 0) {
#endif /* not HAVE_WAITPID */
pjob *p, *p2;
if (WIFSIGNALED(w))
plog(XLOG_ERROR, "Process %d exited with signal %d",
pid, WTERMSIG(w));
#ifdef DEBUG
else
dlog("Process %d exited with status %d",
pid, WEXITSTATUS(w));
#endif /* DEBUG */
for (p = AM_FIRST(pjob, &proc_wait_list);
p2 = NEXT(pjob, p), p != HEAD(pjob, &proc_wait_list);
p = p2) {
if (p->pid == pid) {
p->w = w;
wakeupjob(p);
break;
}
} /* end of for loop */
#ifdef DEBUG
if (!p)
dlog("can't locate task block for pid %d", pid);
#endif /* DEBUG */
/*
* Must count down children inside the while loop, otherwise we won't
* count them all, and NumChild (and later backoff) will be set
* incorrectly. SH/RUNIT 940519.
*/
if (--NumChild < 0)
NumChild = 0;
} /* end of "while wait..." loop */
#ifdef REINSTALL_SIGNAL_HANDLER
signal(sig, sigchld);
#endif /* REINSTALL_SIGNAL_HANDLER */
if (select_intr_valid)
longjmp(select_intr, sig);
}
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