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/* $OpenBSD: kern_kthread.c,v 1.32 2013/03/28 16:55:25 deraadt Exp $ */
/* $NetBSD: kern_kthread.c,v 1.3 1998/12/22 21:21:36 kleink Exp $ */
/*-
* Copyright (c) 1998, 1999 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.
*
* 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>
#include <sys/malloc.h>
#include <sys/queue.h>
/*
* note that stdarg.h and the ansi style va_start macro is used for both
* ansi and traditional c compilers.
* XXX: this requires that stdarg.h define: va_alist and va_dcl
*/
#include <sys/stdarg.h>
int kthread_create_now;
/*
* Fork a kernel thread. Any process can request this to be done.
* The VM space and limits, etc. will be shared with proc0.
*/
int
kthread_create(void (*func)(void *), void *arg,
struct proc **newpp, const char *fmt, ...)
{
struct proc *p;
int error;
va_list ap;
/*
* First, create the new process. Share the memory, file
* descriptors and don't leave the exit status around for the
* parent to wait for.
*/
error = fork1(&proc0, 0, FORK_SHAREVM|FORK_SHAREFILES|FORK_NOZOMBIE|
FORK_SIGHAND, NULL, 0, func, arg, NULL, &p);
if (error)
return (error);
/*
* Mark it as a system process.
*/
atomic_setbits_int(&p->p_flag, P_SYSTEM);
/* Name it as specified. */
va_start(ap, fmt);
vsnprintf(p->p_comm, sizeof p->p_comm, fmt, ap);
va_end(ap);
/* All done! */
if (newpp != NULL)
*newpp = p;
return (0);
}
/*
* Cause a kernel thread to exit. Assumes the exiting thread is the
* current context.
*/
void
kthread_exit(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), EXIT_NORMAL);
/*
* XXX Fool the compiler. Making exit1() __dead is a can
* XXX of worms right now.
*/
for (;;);
}
struct kthread_q {
SIMPLEQ_ENTRY(kthread_q) kq_q;
void (*kq_func)(void *);
void *kq_arg;
};
SIMPLEQ_HEAD(, kthread_q) kthread_q = SIMPLEQ_HEAD_INITIALIZER(kthread_q);
/*
* Defer the creation of a kernel thread. Once the standard kernel threads
* and processes have been created, this queue will be run to callback to
* the caller to create threads for e.g. file systems and device drivers.
*/
void
kthread_create_deferred(void (*func)(void *), void *arg)
{
struct kthread_q *kq;
if (kthread_create_now) {
(*func)(arg);
return;
}
kq = malloc(sizeof *kq, M_TEMP, M_NOWAIT|M_ZERO);
if (kq == NULL)
panic("unable to allocate kthread_q");
kq->kq_func = func;
kq->kq_arg = arg;
SIMPLEQ_INSERT_TAIL(&kthread_q, kq, kq_q);
}
void
kthread_run_deferred_queue(void)
{
struct kthread_q *kq;
/* No longer need to defer kthread creation. */
kthread_create_now = 1;
while ((kq = SIMPLEQ_FIRST(&kthread_q)) != NULL) {
SIMPLEQ_REMOVE_HEAD(&kthread_q, kq_q);
(*kq->kq_func)(kq->kq_arg);
free(kq, M_TEMP);
}
}
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