1 /*
2 * Copyright (c) 1999 Peter Wemm <peter@FreeBSD.org>
3 * All rights reserved.
4 *
5 * Redistribution and use in source and binary forms, with or without
6 * modification, are permitted provided that the following conditions
7 * are met:
8 * 1. Redistributions of source code must retain the above copyright
9 * notice, this list of conditions and the following disclaimer.
10 * 2. Redistributions in binary form must reproduce the above copyright
11 * notice, this list of conditions and the following disclaimer in the
12 * documentation and/or other materials provided with the distribution.
13 *
14 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
15 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
16 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
17 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
18 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
19 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
20 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
21 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
22 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
23 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
24 * SUCH DAMAGE.
25 *
26 * $FreeBSD: releng/5.0/sys/kern/kern_kthread.c 104354 2002-10-02 07:44:29Z scottl $
27 */
28
29 #include <sys/param.h>
30 #include <sys/systm.h>
31 #include <sys/kthread.h>
32 #include <sys/lock.h>
33 #include <sys/mutex.h>
34 #include <sys/proc.h>
35 #include <sys/resourcevar.h>
36 #include <sys/signalvar.h>
37 #include <sys/sx.h>
38 #include <sys/unistd.h>
39 #include <sys/wait.h>
40
41 #include <machine/stdarg.h>
42
43 /*
44 * Start a kernel process. This is called after a fork() call in
45 * mi_startup() in the file kern/init_main.c.
46 *
47 * This function is used to start "internal" daemons and intended
48 * to be called from SYSINIT().
49 */
50 void
51 kproc_start(udata)
52 const void *udata;
53 {
54 const struct kproc_desc *kp = udata;
55 int error;
56
57 error = kthread_create((void (*)(void *))kp->func, NULL,
58 kp->global_procpp, 0, 0, "%s", kp->arg0);
59 if (error)
60 panic("kproc_start: %s: error %d", kp->arg0, error);
61 }
62
63 /*
64 * Create a kernel process/thread/whatever. It shares its address space
65 * with proc0 - ie: kernel only.
66 *
67 * func is the function to start.
68 * arg is the parameter to pass to function on first startup.
69 * newpp is the return value pointing to the thread's struct proc.
70 * flags are flags to fork1 (in unistd.h)
71 * fmt and following will be *printf'd into (*newpp)->p_comm (for ps, etc.).
72 */
73 int
74 kthread_create(void (*func)(void *), void *arg,
75 struct proc **newpp, int flags, int pages, const char *fmt, ...)
76 {
77 int error;
78 va_list ap;
79 struct thread *td;
80 struct proc *p2;
81
82 if (!proc0.p_stats /* || proc0.p_stats->p_start.tv_sec == 0 */)
83 panic("kthread_create called too soon");
84
85 error = fork1(&thread0, RFMEM | RFFDG | RFPROC | RFSTOPPED | flags,
86 pages, &p2);
87 if (error)
88 return error;
89
90 /* save a global descriptor, if desired */
91 if (newpp != NULL)
92 *newpp = p2;
93
94 /* this is a non-swapped system process */
95 PROC_LOCK(p2);
96 p2->p_flag |= P_SYSTEM | P_KTHREAD;
97 p2->p_procsig->ps_flag |= PS_NOCLDWAIT;
98 _PHOLD(p2);
99 PROC_UNLOCK(p2);
100
101 /* set up arg0 for 'ps', et al */
102 va_start(ap, fmt);
103 vsnprintf(p2->p_comm, sizeof(p2->p_comm), fmt, ap);
104 va_end(ap);
105
106 /* call the processes' main()... */
107 td = FIRST_THREAD_IN_PROC(p2);
108 cpu_set_fork_handler(td, func, arg);
109 TD_SET_CAN_RUN(td);
110
111 /* Delay putting it on the run queue until now. */
112 mtx_lock_spin(&sched_lock);
113 p2->p_sflag |= PS_INMEM;
114 if (!(flags & RFSTOPPED)) {
115 setrunqueue(td);
116 }
117 mtx_unlock_spin(&sched_lock);
118
119 return 0;
120 }
121
122 void
123 kthread_exit(int ecode)
124 {
125 struct thread *td;
126 struct proc *p;
127
128 td = curthread;
129 p = td->td_proc;
130 sx_xlock(&proctree_lock);
131 PROC_LOCK(p);
132 proc_reparent(p, initproc);
133 PROC_UNLOCK(p);
134 sx_xunlock(&proctree_lock);
135 exit1(td, W_EXITCODE(ecode, 0));
136 }
137
138 /*
139 * Advise a kernel process to suspend (or resume) in its main loop.
140 * Participation is voluntary.
141 */
142 int
143 kthread_suspend(struct proc *p, int timo)
144 {
145 /*
146 * Make sure this is indeed a system process and we can safely
147 * use the p_siglist field.
148 */
149 PROC_LOCK(p);
150 if ((p->p_flag & P_KTHREAD) == 0) {
151 PROC_UNLOCK(p);
152 return (EINVAL);
153 }
154 SIGADDSET(p->p_siglist, SIGSTOP);
155 wakeup(p);
156 return msleep(&p->p_siglist, &p->p_mtx, PPAUSE | PDROP, "suspkt", timo);
157 }
158
159 int
160 kthread_resume(struct proc *p)
161 {
162 /*
163 * Make sure this is indeed a system process and we can safely
164 * use the p_siglist field.
165 */
166 PROC_LOCK(p);
167 if ((p->p_flag & P_KTHREAD) == 0) {
168 PROC_UNLOCK(p);
169 return (EINVAL);
170 }
171 SIGDELSET(p->p_siglist, SIGSTOP);
172 PROC_UNLOCK(p);
173 wakeup(&p->p_siglist);
174 return (0);
175 }
176
177 void
178 kthread_suspend_check(struct proc *p)
179 {
180 PROC_LOCK(p);
181 while (SIGISMEMBER(p->p_siglist, SIGSTOP)) {
182 wakeup(&p->p_siglist);
183 msleep(&p->p_siglist, &p->p_mtx, PPAUSE, "ktsusp", 0);
184 }
185 PROC_UNLOCK(p);
186 }
Cache object: aeff2e392dfbed104c6444a94422d250
|