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/*
* Copyright (c) 1999 Peter Wemm <peter@FreeBSD.org>
* All rights reserved.
*
* 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 AUTHOR 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 AUTHOR 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/cdefs.h>
__FBSDID("$FreeBSD$");
#include <sys/param.h>
#include <sys/systm.h>
#include <sys/kthread.h>
#include <sys/lock.h>
#include <sys/mutex.h>
#include <sys/proc.h>
#include <sys/resourcevar.h>
#include <sys/signalvar.h>
#include <sys/sx.h>
#include <sys/unistd.h>
#include <sys/wait.h>
#include <machine/stdarg.h>
/*
* Start a kernel process. This is called after a fork() call in
* mi_startup() in the file kern/init_main.c.
*
* This function is used to start "internal" daemons and intended
* to be called from SYSINIT().
*/
void
kproc_start(udata)
const void *udata;
{
const struct kproc_desc *kp = udata;
int error;
error = kthread_create((void (*)(void *))kp->func, NULL,
kp->global_procpp, 0, 0, "%s", kp->arg0);
if (error)
panic("kproc_start: %s: error %d", kp->arg0, error);
}
/*
* Create a kernel process/thread/whatever. It shares its address space
* with proc0 - ie: kernel only.
*
* func is the function to start.
* arg is the parameter to pass to function on first startup.
* newpp is the return value pointing to the thread's struct proc.
* flags are flags to fork1 (in unistd.h)
* fmt and following will be *printf'd into (*newpp)->p_comm (for ps, etc.).
*/
int
kthread_create(void (*func)(void *), void *arg,
struct proc **newpp, int flags, int pages, const char *fmt, ...)
{
int error;
va_list ap;
struct thread *td;
struct proc *p2;
if (!proc0.p_stats)
panic("kthread_create called too soon");
error = fork1(&thread0, RFMEM | RFFDG | RFPROC | RFSTOPPED | flags,
pages, &p2);
if (error)
return error;
/* save a global descriptor, if desired */
if (newpp != NULL)
*newpp = p2;
/* this is a non-swapped system process */
PROC_LOCK(p2);
p2->p_flag |= P_SYSTEM | P_KTHREAD;
mtx_lock(&p2->p_sigacts->ps_mtx);
p2->p_sigacts->ps_flag |= PS_NOCLDWAIT;
mtx_unlock(&p2->p_sigacts->ps_mtx);
_PHOLD(p2);
PROC_UNLOCK(p2);
/* set up arg0 for 'ps', et al */
va_start(ap, fmt);
vsnprintf(p2->p_comm, sizeof(p2->p_comm), fmt, ap);
va_end(ap);
/* call the processes' main()... */
td = FIRST_THREAD_IN_PROC(p2);
cpu_set_fork_handler(td, func, arg);
TD_SET_CAN_RUN(td);
/* Delay putting it on the run queue until now. */
if (!(flags & RFSTOPPED)) {
mtx_lock_spin(&sched_lock);
setrunqueue(td);
mtx_unlock_spin(&sched_lock);
}
return 0;
}
void
kthread_exit(int ecode)
{
struct thread *td;
struct proc *p;
td = curthread;
p = td->td_proc;
sx_xlock(&proctree_lock);
PROC_LOCK(p);
proc_reparent(p, initproc);
PROC_UNLOCK(p);
sx_xunlock(&proctree_lock);
exit1(td, W_EXITCODE(ecode, 0));
}
/*
* Advise a kernel process to suspend (or resume) in its main loop.
* Participation is voluntary.
*/
int
kthread_suspend(struct proc *p, int timo)
{
/*
* Make sure this is indeed a system process and we can safely
* use the p_siglist field.
*/
PROC_LOCK(p);
if ((p->p_flag & P_KTHREAD) == 0) {
PROC_UNLOCK(p);
return (EINVAL);
}
SIGADDSET(p->p_siglist, SIGSTOP);
wakeup(p);
return msleep(&p->p_siglist, &p->p_mtx, PPAUSE | PDROP, "suspkt", timo);
}
int
kthread_resume(struct proc *p)
{
/*
* Make sure this is indeed a system process and we can safely
* use the p_siglist field.
*/
PROC_LOCK(p);
if ((p->p_flag & P_KTHREAD) == 0) {
PROC_UNLOCK(p);
return (EINVAL);
}
SIGDELSET(p->p_siglist, SIGSTOP);
PROC_UNLOCK(p);
wakeup(&p->p_siglist);
return (0);
}
void
kthread_suspend_check(struct proc *p)
{
PROC_LOCK(p);
while (SIGISMEMBER(p->p_siglist, SIGSTOP)) {
wakeup(&p->p_siglist);
msleep(&p->p_siglist, &p->p_mtx, PPAUSE, "ktsusp", 0);
}
PROC_UNLOCK(p);
}
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