xref: /illumos-gate/usr/src/cmd/lp/cmd/lpsched/schedule.c (revision 0a44ef6d)

/*
 * CDDL HEADER START
 *
 * The contents of this file are subject to the terms of the
 * Common Development and Distribution License (the "License").
 * You may not use this file except in compliance with the License.
 *
 * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
 * or http://www.opensolaris.org/os/licensing.
 * See the License for the specific language governing permissions
 * and limitations under the License.
 *
 * When distributing Covered Code, include this CDDL HEADER in each
 * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
 * If applicable, add the following below this CDDL HEADER, with the
 * fields enclosed by brackets "[]" replaced with your own identifying
 * information: Portions Copyright [yyyy] [name of copyright owner]
 *
 * CDDL HEADER END
 */

/*
 * Copyright 2006 Sun Microsystems, Inc.  All rights reserved.
 * Use is subject to license terms.
 */

/*	Copyright (c) 1984, 1986, 1987, 1988, 1989 AT&T	*/
/*	  All Rights Reserved  	*/


#pragma ident	"%Z%%M%	%I%	%E% SMI"

#include "stdarg.h"
#include "lpsched.h"
#include <syslog.h>

extern int isStartingForms;

typedef struct later {
	struct later *		next;
	int			event,
				ticks;
	union arg {
		PSTATUS *		printer;
		RSTATUS *		request;
		FSTATUS *		form;
	}			arg;
}			LATER;

static LATER		LaterHead	= { 0 },
			TempHead;

static void		ev_interf(PSTATUS *);
static void		ev_message(PSTATUS *);
static void		ev_form_message(FSTATUS *);
static int		ev_slowf(RSTATUS *);
static int		ev_notify(RSTATUS *);

static EXEC		*find_exec_slot(EXEC **);

static char *_event_name(int event)
{
	static char *_names[] = {
	"", "EV_SLOWF", "EV_INTERF", "EV_NOTIFY", "EV_LATER", "EV_ALARM",
	"EV_MESSAGE", "EV_ENABLE", "EV_FORM_MESSAGE", NULL };

	if ((event < 0) || (event > EV_FORM_MESSAGE))
		return ("BAD_EVENT");
	else
		return (_names[event]);
}

/*
 * schedule() - SCHEDULE BY EVENT
 */

/*VARARGS1*/
void
schedule(int event, ...)
{
	va_list			ap;

	LATER *			plprev;
	LATER *			pl;
	LATER *			plnext	= 0;

	register PSTATUS *	pps;
	register RSTATUS *	prs;
	register FSTATUS *	pfs;

	int i;
	/*
	 * If we're in the process of shutting down, don't
	 * schedule anything.
	 */
	syslog(LOG_DEBUG, "schedule(%s)", _event_name(event));

	if (Shutdown)
		return;

	va_start (ap, event);

	/*
	 * If we're still in the process of starting up, don't start
	 * anything! Schedule it for one tick later. While we're starting
	 * ticks aren't counted, so the events won't be started.
	 * HOWEVER, with a count of 1, a single EV_ALARM after we're
	 * finished starting will be enough to clear all things scheduled
	 * for later.
	 */
	if (Starting) {
		switch (event) {

		case EV_INTERF:
		case EV_ENABLE:
			pps = va_arg(ap, PSTATUS *);
			schedule (EV_LATER, 1, event, pps);
			goto Return;

		case EV_SLOWF:
		case EV_NOTIFY:
			prs = va_arg(ap, RSTATUS *);
			schedule (EV_LATER, 1, event, prs);
			goto Return;

		case EV_MESSAGE:
			pps = va_arg(ap, PSTATUS *);
			schedule (EV_LATER, 1, event, pps);
			goto Return;

		case EV_FORM_MESSAGE:
			pfs = va_arg(ap, FSTATUS *);
			schedule (EV_LATER, 1, event, pfs);
			goto Return;

		case EV_LATER:
			/*
			 * This is okay--in fact it may be us!
			 */
			break;

		case EV_ALARM:
			/*
			 * The alarm will go off again, hold off for now.
			 */
			goto Return;

		}
	}

	/*
	 * Schedule something:
	 */
	switch (event) {

	case EV_INTERF:
		if ((pps = va_arg(ap, PSTATUS *)) != NULL)
			ev_interf (pps);

		else
			for (i = 0; PStatus != NULL && PStatus[i] != NULL; i++)
				ev_interf (PStatus[i]);

		break;

	/*
	 * The EV_ENABLE event is used to get a printer going again
	 * after waiting for a fault to be cleared. We used to use
	 * just the EV_INTERF event, but this wasn't enough: For
	 * requests that can go on several different printers (e.g.
	 * queued for class, queued for ``any''), a printer is
	 * arbitrarily assigned. The EV_INTERF event just checks
	 * assignments, not possibilities, so a printer with no
	 * assigned requests but still eligible to handle one or
	 * more requests would never automatically start up again after
	 * a fault. The EV_ENABLE event calls "enable()" which eventually
	 * gets around to invoking the EV_INTERF event. However, it first
	 * calls "queue_attract()" to get an eligible request assigned
	 * so that things proceed. This also makes sense from the
	 * following standpoint: The documented method of getting a
	 * printer going, while it is waiting for auto-retry, is to
	 * manually issue the enable command!
	 *
	 * Note: "enable()" will destroy the current record of the fault,
	 * so if the fault is still with us any new alert will not include
	 * the history of each repeated fault. This is a plus and a minus,
	 * usually a minus: While a repeated fault may occasionally show
	 * a varied record, usually the same reason is given each time;
	 * before switching to EV_ENABLE we typically saw a boring, long
	 * list of identical reasons.
	 */
	case EV_ENABLE:
		if ((pps = va_arg(ap, PSTATUS *)) != NULL)
			enable (pps);
		else
			for (i = 0; PStatus != NULL && PStatus[i] != NULL; i++)
				enable (PStatus[i]);
		break;

	case EV_SLOWF:
		if ((prs = va_arg(ap, RSTATUS *)) != NULL)
			(void) ev_slowf (prs);
		else
			for (prs = Request_List; prs && ev_slowf(prs) != -1;
				prs = prs->next);
		break;

	case EV_NOTIFY:
		if ((prs = va_arg(ap, RSTATUS *)) != NULL)
			(void) ev_notify (prs);
		else
			for (prs = Request_List; prs && ev_notify(prs) != -1;
				prs = prs->next);
		break;

	case EV_MESSAGE:
		pps = va_arg(ap, PSTATUS *);
		ev_message(pps);
		break;

	case EV_FORM_MESSAGE:
		pfs = va_arg(ap, FSTATUS *);
		ev_form_message(pfs);
		break;

	case EV_LATER:
		pl = (LATER *)Malloc(sizeof (LATER));

		if (!LaterHead.next)
			alarm (CLOCK_TICK);

		pl->next = LaterHead.next;
		LaterHead.next = pl;

		pl->ticks = va_arg(ap, int);
		pl->event = va_arg(ap, int);
		switch (pl->event) {

		case EV_MESSAGE:
		case EV_INTERF:
		case EV_ENABLE:
			pl->arg.printer = va_arg(ap, PSTATUS *);
			if (pl->arg.printer)
				pl->arg.printer->status |= PS_LATER;
			break;

		case EV_FORM_MESSAGE:
			pl->arg.form = va_arg(ap, FSTATUS *);
			break;

		case EV_SLOWF:
		case EV_NOTIFY:
			pl->arg.request = va_arg(ap, RSTATUS *);
			break;

		}
		break;

	case EV_ALARM:
		Sig_Alrm = 0;

		/*
		 * The act of scheduling some of the ``laters'' may
		 * cause new ``laters'' to be added to the list.
		 * To ease the handling of the linked list, we first
		 * run through the list and move all events ready to
		 * be scheduled to another list. Then we schedule the
		 * events off the new list. This leaves the main ``later''
		 * list ready for new events.
		 */
		TempHead.next = 0;
		for (pl = (plprev = &LaterHead)->next; pl; pl = plnext) {
			plnext = pl->next;
			if (--pl->ticks)
				plprev = pl;
			else {
				plprev->next = plnext;

				pl->next = TempHead.next;
				TempHead.next = pl;
			}
		}

		for (pl = TempHead.next; pl; pl = plnext) {
			plnext = pl->next;
			switch (pl->event) {

			case EV_MESSAGE:
			case EV_INTERF:
			case EV_ENABLE:
				pl->arg.printer->status &= ~PS_LATER;
				schedule (pl->event, pl->arg.printer);
				break;

			case EV_FORM_MESSAGE:
				schedule (pl->event, pl->arg.form);
				break;

			case EV_SLOWF:
			case EV_NOTIFY:
				schedule (pl->event, pl->arg.request);
				break;

			}
			Free ((char *)pl);
		}

		if (LaterHead.next)
			alarm (CLOCK_TICK);
		break;

	}

Return:	va_end (ap);

	return;
}

/*
 * maybe_schedule() - MAYBE SCHEDULE SOMETHING FOR A REQUEST
 */

void
maybe_schedule(RSTATUS *prs)
{
	/*
	 * Use this routine if a request has been changed by some
	 * means so that it is ready for filtering or printing,
	 * but a previous filtering or printing process for this
	 * request MAY NOT have finished yet. If a process is still
	 * running, then the cleanup of that process will cause
	 * "schedule()" to be called. Calling "schedule()" regardless
	 * might make another request slip ahead of this request.
	 */

	/*
	 * "schedule()" will refuse if this request is filtering.
	 * It will also refuse if the request ``was'' filtering
	 * but the filter was terminated in "validate_request()",
	 * because we can not have heard from the filter process
	 * yet. Also, when called with a particular request,
	 * "schedule()" won't slip another request ahead.
	 */
	if (NEEDS_FILTERING(prs))
		schedule (EV_SLOWF, prs);

	else if (!(prs->request->outcome & RS_STOPPED))
		schedule (EV_INTERF, prs->printer);

	return;
}

static void
ev_message(PSTATUS *pps)
{
	register RSTATUS	*prs;
	char			toSelf;

	syslog(LOG_DEBUG, "ev_message(%s)",
	       (pps && pps->request && pps->request->req_file ?
		pps->request->req_file : "NULL"));

	toSelf = 0;
	for (prs = Request_List; prs != NULL; prs = prs->next)
		if (prs->printer == pps) {
			note("prs (%d) pps (%d)\n", prs, pps);
			if (!toSelf) {
				toSelf = 1;
				exec(EX_FAULT_MESSAGE, pps, prs);
			}
		}
}

static void
ev_form_message_body(FSTATUS *pfs, RSTATUS *prs, char *toSelf, char ***sysList)
{
	syslog(LOG_DEBUG, "ev_form_message_body(%s, %d, 0x%x)",
	      (pfs && pfs->form && pfs->form->name ? pfs->form->name : "NULL"),
	      (toSelf ? *toSelf : 0),
		sysList);

	if (!*toSelf) {
		*toSelf = 1;
		exec(EX_FORM_MESSAGE, pfs);
	}
}

static void
ev_form_message(FSTATUS *pfs)
{
	register RSTATUS	*prs;
	char **sysList;
	char toSelf;

	syslog(LOG_DEBUG, "ev_form_message(%s)",
	       (pfs && pfs->form && pfs->form->name ?
		pfs->form->name : "NULL"));

	toSelf = 0;
	sysList = NULL;

	for (prs = Request_List; prs != NULL; prs = prs->next)
		if (prs->form == pfs)
			ev_form_message_body(pfs, prs, &toSelf, &sysList);

	if (NewRequest && (NewRequest->form == pfs))
		ev_form_message_body(pfs, NewRequest, &toSelf, &sysList);

	freelist(sysList);
}

/*
 * ev_interf() - CHECK AND EXEC INTERFACE PROGRAM
 */

/*
 * Macro to check if the request needs a print wheel or character set (S)
 * and the printer (P) has it mounted or can select it. Since the request
 * has already been approved for the printer, we don't have to check the
 * character set, just the mount. If the printer has selectable character
 * sets, there's nothing to check so the request is ready to print.
 */
#define	MATCH(PRS, PPS) (\
		!(PPS)->printer->daisy || \
		!(PRS)->pwheel_name || \
		!((PRS)->status & RSS_PWMAND) || \
		STREQU((PRS)->pwheel_name, NAME_ANY) || \
		((PPS)->pwheel_name && \
		STREQU((PPS)->pwheel_name, (PRS)->pwheel_name)))


static void
ev_interf(PSTATUS *pps)
{
	register RSTATUS	*prs;

	syslog(LOG_DEBUG, "ev_interf(%s)",
	       (pps && pps->request && pps->request->req_file ?
		pps->request->req_file : "NULL"));


	/*
	 * If the printer isn't tied up doing something
	 * else, and isn't disabled, see if there is a request
	 * waiting to print on it. Note: We don't include
	 * PS_FAULTED here, because simply having a printer
	 * fault (without also being disabled) isn't sufficient
	 * to keep us from trying again. (In fact, we HAVE TO
	 * try again, to see if the fault has gone away.)
	 *
	 * NOTE: If the printer is faulted but the filter controlling
	 * the printer is waiting for the fault to clear, a
	 * request will still be attached to the printer, as
	 * evidenced by "pps->request", so we won't try to
	 * schedule another request!
	 */
	if (pps->request || pps->status & (PS_DISABLED|PS_LATER|PS_BUSY))
		return;

	for (prs = Request_List; prs != NULL; prs = prs->next) {
		if ((prs->printer == pps) && (qchk_waiting(prs)) &&
		    isFormUsableOnPrinter(pps, prs->form) && MATCH(prs, pps)) {
		/*
		 * Just because the printer isn't busy and the
		 * request is assigned to this printer, don't get the
		 * idea that the request can't be printing (RS_ACTIVE),
		 * because another printer may still have the request
		 * attached but we've not yet heard from the child
		 * process controlling that printer.
		 *
		 * We have the waiting request, we have
		 * the ready (local) printer. If the exec fails
		 * because the fork failed, schedule a
		 * try later and claim we succeeded. The
		 * later attempt will sort things out,
		 * e.g. will re-schedule if the fork fails
		 * again.
		 */
			pps->request = prs;
			if (exec(EX_INTERF, pps) == 0) {
				pps->status |= PS_BUSY;
				return;
			}
			pps->request = 0;
			if (errno == EAGAIN) {
				load_str (&pps->dis_reason, CUZ_NOFORK);
				schedule (EV_LATER, WHEN_FORK, EV_ENABLE, pps);
				return;
			}
		}
	}

	return;
}

/*
 * ev_slowf() - CHECK AND EXEC SLOW FILTER
 */

static int
ev_slowf(RSTATUS *prs)
{
	register EXEC		*ep;

	syslog(LOG_DEBUG, "ev_slowf(%s)",
	       (prs && prs->req_file ? prs->req_file : "NULL"));

	/*
	 * Return -1 if no more can be executed (no more exec slots)
	 * or if it's unwise to execute any more (fork failed).
	 */

	if (!(ep = find_exec_slot(Exec_Slow))) {
		syslog(LOG_DEBUG, "ev_slowf(%s): no slot",
	       		(prs && prs->req_file ? prs->req_file : "NULL"));
		return (-1);
	}

	if (!(prs->request->outcome & (RS_DONE|RS_HELD|RS_ACTIVE)) &&
	    NEEDS_FILTERING(prs)) {
		(prs->exec = ep)->ex.request = prs;
		if (exec(EX_SLOWF, prs) != 0) {
			ep->ex.request = 0;
			prs->exec = 0;
			if (errno == EAGAIN) {
				schedule (EV_LATER, WHEN_FORK, EV_SLOWF, prs);
				return (-1);
			}
		}
	}
	return (0);
}

/*
 * ev_notify() - CHECK AND EXEC NOTIFICATION
 */

static int
ev_notify(RSTATUS *prs)
{
	register EXEC		*ep;

	syslog(LOG_DEBUG, "ev_notify(%s)",
	       (prs && prs->req_file ? prs->req_file : "NULL"));

	/*
	 * Return -1 if no more can be executed (no more exec slots)
	 * or if it's unwise to execute any more (fork failed, already
	 * sent one to remote side).
	 */

	/*
	 * If the job came from a remote machine, we forward the
	 * outcome of the request to the network manager for sending
	 * to the remote side.
	 */
	if (prs->request->actions & ACT_NOTIFY) {
		if (prs->request->outcome & RS_NOTIFY) {
			prs->request->actions &= ~ACT_NOTIFY;
			return (0);  /* but try another request */
		}
	/*
	 * If the job didn't come from a remote system,
	 * we'll try to start a process to send the notification
	 * to the user. But we only allow so many notifications
	 * to run at the same time, so we may not be able to
	 * do it.
	 */
	} else if (!(ep = find_exec_slot(Exec_Notify)))
		return (-1);

	else if (prs->request->outcome & RS_NOTIFY &&
		!(prs->request->outcome & RS_NOTIFYING)) {

		(prs->exec = ep)->ex.request = prs;
		if (exec(EX_NOTIFY, prs) != 0) {
			ep->ex.request = 0;
			prs->exec = 0;
			if (errno == EAGAIN) {
				schedule (EV_LATER, WHEN_FORK, EV_NOTIFY, prs);
				return (-1);
			}
		}
	}
	return (0);
}


/*
 * find_exec_slot() - FIND AVAILABLE EXEC SLOT
 */

static EXEC *
find_exec_slot(EXEC **exec_table)
{
	int i;

	for (i = 0; exec_table[i] != NULL; i++)
		if (exec_table[i]->pid == 0)
			return (exec_table[i]);

	syslog(LOG_DEBUG, "find_exec_slot(0x%8.8x): after %d, no slots",
			exec_table, i);
	return (0);
}