ndet_s_wait.c

操作系统SunOS 4.1.3版本的源码

#ifndef	lint
#ifdef sccs
static	char sccsid[] = "@(#)ndet_s_wait.c 1.1 92/07/30 Copyr 1985 Sun Micro";
#endif
#endif

/*
 * Copyright (c) 1985 by Sun Microsystems, Inc.
 */

/*
 * Ndet_s_wait.c - Implement the notify_set_wait3_func interface.
 */

#include <sunwindow/ntfy.h>
#include <sunwindow/ndet.h>
#include <sunwindow/ndis.h>
#include <sunwindow/nint.h>
#include <signal.h>

extern Notify_func
notify_set_wait3_func(nclient, func, pid)
	Notify_client nclient;
	Notify_func func;
	int pid;
{
	Notify_func old_func = NOTIFY_FUNC_NULL;
	register NTFY_CLIENT *client;
	NTFY_CONDITION *condition;

	NTFY_BEGIN_CRITICAL;
	/*
	 * Don't check pid so that we can avoid the race condition of
	 * pid having exited before calling this routine.  It still
	 * needs to be reaped.
	 */
	/* Find/create client that corresponds to nclient */
	if ((client = ntfy_new_nclient(&ndet_clients, nclient,
            &ndet_client_latest)) == NTFY_CLIENT_NULL)
		goto Done;
	/* Find/create condition */
	if ((condition = ntfy_new_condition(&(client->conditions), NTFY_WAIT3,
	    &(client->condition_latest), (NTFY_DATA)pid, NTFY_USE_DATA)) ==
	    NTFY_CONDITION_NULL)
		goto Done;
	/* Exchange functions */
	old_func = nint_set_func(condition, func);
	/* Remove condition if func is null */
	if (func == NOTIFY_FUNC_NULL) {
		/* Remove from dispatcher */
		ndis_flush_wait3(nclient, pid);
		ntfy_unset_condition(&ndet_clients, client, condition,
		    &ndet_client_latest, NTFY_NDET);
	} else
		/* Make sure we are catching SIGCHLD before return */
		ndet_enable_sig(SIGCHLD);
	/*
	 * Have notifier check for SIGCHLD changes next time around loop.
	 * Will confirm signal handling at this time.
	 */
	ndet_flags |= NDET_WAIT3_CHANGE;
	/*
	 * Fake a SIGCHLD so that we do a wait3 in the case of
	 * pid having exited before calling or during this routine.
	 * It still needs to be reaped.
	 */
	if (func != NOTIFY_FUNC_NULL)
		ndet_sigs_received |= SIG_BIT(SIGCHLD);
Done:
	NTFY_END_CRITICAL;
	return(old_func);
}