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
27 #include <sys/cdefs.h>
28 __FBSDID("$FreeBSD: releng/6.2/sys/kern/kern_kthread.c 164286 2006-11-14 20:42:41Z cvs2svn $");
29
30 #include <sys/param.h>
31 #include <sys/systm.h>
32 #include <sys/kthread.h>
33 #include <sys/lock.h>
34 #include <sys/mutex.h>
35 #include <sys/proc.h>
36 #include <sys/resourcevar.h>
37 #include <sys/signalvar.h>
38 #include <sys/sx.h>
39 #include <sys/unistd.h>
40 #include <sys/wait.h>
41
42 #include <machine/stdarg.h>
43
44 /*
45 * Start a kernel process. This is called after a fork() call in
46 * mi_startup() in the file kern/init_main.c.
47 *
48 * This function is used to start "internal" daemons and intended
49 * to be called from SYSINIT().
50 */
51 void
52 kproc_start(udata)
53 const void *udata;
54 {
55 const struct kproc_desc *kp = udata;
56 int error;
57
58 error = kthread_create((void (*)(void *))kp->func, NULL,
59 kp->global_procpp, 0, 0, "%s", kp->arg0);
60 if (error)
61 panic("kproc_start: %s: error %d", kp->arg0, error);
62 }
63
64 /*
65 * Create a kernel process/thread/whatever. It shares its address space
66 * with proc0 - ie: kernel only.
67 *
68 * func is the function to start.
69 * arg is the parameter to pass to function on first startup.
70 * newpp is the return value pointing to the thread's struct proc.
71 * flags are flags to fork1 (in unistd.h)
72 * fmt and following will be *printf'd into (*newpp)->p_comm (for ps, etc.).
73 */
74 int
75 kthread_create(void (*func)(void *), void *arg,
76 struct proc **newpp, int flags, int pages, const char *fmt, ...)
77 {
78 int error;
79 va_list ap;
80 struct thread *td;
81 struct proc *p2;
82
83 if (!proc0.p_stats)
84 panic("kthread_create called too soon");
85
86 error = fork1(&thread0, RFMEM | RFFDG | RFPROC | RFSTOPPED | flags,
87 pages, &p2);
88 if (error)
89 return error;
90
91 /* save a global descriptor, if desired */
92 if (newpp != NULL)
93 *newpp = p2;
94
95 /* this is a non-swapped system process */
96 PROC_LOCK(p2);
97 p2->p_flag |= P_SYSTEM | P_KTHREAD;
98 mtx_lock(&p2->p_sigacts->ps_mtx);
99 p2->p_sigacts->ps_flag |= PS_NOCLDWAIT;
100 mtx_unlock(&p2->p_sigacts->ps_mtx);
101 PROC_UNLOCK(p2);
102
103 /* set up arg0 for 'ps', et al */
104 va_start(ap, fmt);
105 vsnprintf(p2->p_comm, sizeof(p2->p_comm), fmt, ap);
106 va_end(ap);
107
108 /* call the processes' main()... */
109 td = FIRST_THREAD_IN_PROC(p2);
110 cpu_set_fork_handler(td, func, arg);
111 TD_SET_CAN_RUN(td);
112
113 /* Delay putting it on the run queue until now. */
114 if (!(flags & RFSTOPPED)) {
115 mtx_lock_spin(&sched_lock);
116 setrunqueue(td, SRQ_BORING);
117 mtx_unlock_spin(&sched_lock);
118 }
119
120 return 0;
121 }
122
123 void
124 kthread_exit(int ecode)
125 {
126 struct thread *td;
127 struct proc *p;
128
129 td = curthread;
130 p = td->td_proc;
131 sx_xlock(&proctree_lock);
132 PROC_LOCK(p);
133 proc_reparent(p, initproc);
134 PROC_UNLOCK(p);
135 sx_xunlock(&proctree_lock);
136 exit1(td, W_EXITCODE(ecode, 0));
137 }
138
139 /*
140 * Advise a kernel process to suspend (or resume) in its main loop.
141 * Participation is voluntary.
142 */
143 int
144 kthread_suspend(struct proc *p, int timo)
145 {
146 /*
147 * Make sure this is indeed a system process and we can safely
148 * use the p_siglist field.
149 */
150 PROC_LOCK(p);
151 if ((p->p_flag & P_KTHREAD) == 0) {
152 PROC_UNLOCK(p);
153 return (EINVAL);
154 }
155 SIGADDSET(p->p_siglist, SIGSTOP);
156 wakeup(p);
157 return msleep(&p->p_siglist, &p->p_mtx, PPAUSE | PDROP, "suspkt", timo);
158 }
159
160 int
161 kthread_resume(struct proc *p)
162 {
163 /*
164 * Make sure this is indeed a system process and we can safely
165 * use the p_siglist field.
166 */
167 PROC_LOCK(p);
168 if ((p->p_flag & P_KTHREAD) == 0) {
169 PROC_UNLOCK(p);
170 return (EINVAL);
171 }
172 SIGDELSET(p->p_siglist, SIGSTOP);
173 PROC_UNLOCK(p);
174 wakeup(&p->p_siglist);
175 return (0);
176 }
177
178 void
179 kthread_suspend_check(struct proc *p)
180 {
181 PROC_LOCK(p);
182 while (SIGISMEMBER(p->p_siglist, SIGSTOP)) {
183 wakeup(&p->p_siglist);
184 msleep(&p->p_siglist, &p->p_mtx, PPAUSE, "ktsusp", 0);
185 }
186 PROC_UNLOCK(p);
187 }
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