/*	$NetBSD: kern_kthread.c,v 1.1 1998/11/11 22:44:24 thorpej Exp $	*/

/*-
 * Copyright (c) 1998 The NetBSD Foundation, Inc.
 * All rights reserved.
 *
 * This code is derived from software contributed to The NetBSD Foundation
 * by Jason R. Thorpe of the Numerical Aerospace Simulation Facility,
 * NASA Ames Research Center.
 *
 * 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 NetBSD
 *	Foundation, Inc. and its contributors.
 * 4. Neither the name of The NetBSD Foundation 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 NETBSD FOUNDATION, INC. 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 FOUNDATION 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.
 */

#include <sys/param.h>
#include <sys/systm.h>
#include <sys/kernel.h>
#include <sys/kthread.h>
#include <sys/proc.h>
#include <sys/wait.h>

/*
 * note that stdarg.h and the ansi style va_start macro is used for both
 * ansi and traditional c complers.
 * XXX: this requires that stdarg.h define: va_alist and va_dcl
 */
#include <machine/stdarg.h>

/*
 * Fork a kernel thread.  Any process can request this to be done.
 * The VM space and limits, etc. will be shared with proc0.
 */
int
#ifdef __STDC__
kthread_create(void (*func)(void *), void *arg,
    struct proc **newpp, const char *fmt, ...)
#else
kthread_create(func, arg, newpp, fmt, va_alist)
	void (*func) __P((void *));
	void *arg;
	struct proc **newpp;
	const char *fmt;
	va_dcl
#endif
{
	struct proc *p2;
	int error;
	va_list ap;

	/* First, create the new process. */
	error = fork1(&proc0, FORK_SHAREVM, NULL, &p2);
	if (error)
		return (error);

	/*
	 * Mark it as a system process and not a candidate for
	 * swapping.  Set P_NOCLDWAIT so that children are reparented
	 * to init(8) when they exit.  init(8) can easily wait them
	 * out for us.
	 */
	p2->p_flag |= P_INMEM | P_SYSTEM | P_NOCLDWAIT;	/* XXX */

	/* Name it as specified. */
	va_start(ap, fmt);
	vsprintf(p2->p_comm, fmt, ap);
	va_end(ap);

	/* Arrange for it to start at the specified function. */
	cpu_set_kpc(p2, func, arg);

	/* All done! */
	if (newpp != NULL)
		*newpp = p2;
	return (0);
}

/*
 * Cause a kernel thread to exit.  Assumes the exiting thread is the
 * current context.
 */
void
kthread_exit(ecode)
	int ecode;
{

	/*
	 * XXX What do we do with the exit code?  Should we even bother
	 * XXX with it?  The parent (proc0) isn't going to do much with
	 * XXX it.
	 */
	if (ecode != 0)
		printf("WARNING: thread `%s' (%d) exits with status %d\n",
		    curproc->p_comm, curproc->p_pid, ecode);

	exit1(curproc, W_EXITCODE(ecode, 0));

	/*
	 * XXX Fool the compiler.  Making exit1() __noreturn__ is a can
	 * XXX of worms right now.
	 */
	for (;;);
}