1 /* $NetBSD: kern_kthread.c,v 1.15 2003/01/18 10:06:26 thorpej Exp $ */
2
3 /*-
4 * Copyright (c) 1998, 1999 The NetBSD Foundation, Inc.
5 * All rights reserved.
6 *
7 * This code is derived from software contributed to The NetBSD Foundation
8 * by Jason R. Thorpe of the Numerical Aerospace Simulation Facility,
9 * NASA Ames Research Center.
10 *
11 * Redistribution and use in source and binary forms, with or without
12 * modification, are permitted provided that the following conditions
13 * are met:
14 * 1. Redistributions of source code must retain the above copyright
15 * notice, this list of conditions and the following disclaimer.
16 * 2. Redistributions in binary form must reproduce the above copyright
17 * notice, this list of conditions and the following disclaimer in the
18 * documentation and/or other materials provided with the distribution.
19 * 3. All advertising materials mentioning features or use of this software
20 * must display the following acknowledgement:
21 * This product includes software developed by the NetBSD
22 * Foundation, Inc. and its contributors.
23 * 4. Neither the name of The NetBSD Foundation nor the names of its
24 * contributors may be used to endorse or promote products derived
25 * from this software without specific prior written permission.
26 *
27 * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
28 * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
29 * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
30 * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
31 * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
32 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
33 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
34 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
35 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
36 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
37 * POSSIBILITY OF SUCH DAMAGE.
38 */
39
40 #include <sys/cdefs.h>
41 __KERNEL_RCSID(0, "$NetBSD: kern_kthread.c,v 1.15 2003/01/18 10:06:26 thorpej Exp $");
42
43 #include <sys/param.h>
44 #include <sys/systm.h>
45 #include <sys/kernel.h>
46 #include <sys/kthread.h>
47 #include <sys/proc.h>
48 #include <sys/wait.h>
49 #include <sys/malloc.h>
50 #include <sys/queue.h>
51
52 /*
53 * note that stdarg.h and the ansi style va_start macro is used for both
54 * ansi and traditional c complers.
55 * XXX: this requires that stdarg.h define: va_alist and va_dcl
56 */
57 #include <machine/stdarg.h>
58
59 int kthread_create_now;
60
61 /*
62 * Fork a kernel thread. Any process can request this to be done.
63 * The VM space and limits, etc. will be shared with proc0.
64 */
65 int
66 kthread_create1(void (*func)(void *), void *arg,
67 struct proc **newpp, const char *fmt, ...)
68 {
69 struct proc *p2;
70 int error;
71 va_list ap;
72
73 /* First, create the new process. */
74 error = fork1(&lwp0, FORK_SHAREVM | FORK_SHARECWD | FORK_SHAREFILES |
75 FORK_SHARESIGS, SIGCHLD, NULL, 0, func, arg, NULL, &p2);
76 if (__predict_false(error != 0))
77 return (error);
78
79 /*
80 * Mark it as a system process and not a candidate for
81 * swapping. Set P_NOCLDWAIT so that children are reparented
82 * to init(8) when they exit. init(8) can easily wait them
83 * out for us.
84 */
85 p2->p_flag |= P_SYSTEM | P_NOCLDWAIT;
86 LIST_FIRST(&p2->p_lwps)->l_flag |= L_INMEM;
87
88 /* Name it as specified. */
89 va_start(ap, fmt);
90 vsnprintf(p2->p_comm, MAXCOMLEN, fmt, ap);
91 va_end(ap);
92
93 /* All done! */
94 if (newpp != NULL)
95 *newpp = p2;
96 return (0);
97 }
98
99 /*
100 * Cause a kernel thread to exit. Assumes the exiting thread is the
101 * current context.
102 */
103 void
104 kthread_exit(int ecode)
105 {
106
107 /*
108 * XXX What do we do with the exit code? Should we even bother
109 * XXX with it? The parent (proc0) isn't going to do much with
110 * XXX it.
111 */
112 if (ecode != 0)
113 printf("WARNING: thread `%s' (%d) exits with status %d\n",
114 curproc->p_comm, curproc->p_pid, ecode);
115
116 exit1(curlwp, W_EXITCODE(ecode, 0));
117
118 /*
119 * XXX Fool the compiler. Making exit1() __noreturn__ is a can
120 * XXX of worms right now.
121 */
122 for (;;);
123 }
124
125 struct kthread_q {
126 SIMPLEQ_ENTRY(kthread_q) kq_q;
127 void (*kq_func)(void *);
128 void *kq_arg;
129 };
130
131 SIMPLEQ_HEAD(, kthread_q) kthread_q = SIMPLEQ_HEAD_INITIALIZER(kthread_q);
132
133 /*
134 * Defer the creation of a kernel thread. Once the standard kernel threads
135 * and processes have been created, this queue will be run to callback to
136 * the caller to create threads for e.g. file systems and device drivers.
137 */
138 void
139 kthread_create(void (*func)(void *), void *arg)
140 {
141 struct kthread_q *kq;
142
143 if (kthread_create_now) {
144 (*func)(arg);
145 return;
146 }
147
148 kq = malloc(sizeof(*kq), M_TEMP, M_NOWAIT);
149 if (kq == NULL)
150 panic("unable to allocate kthread_q");
151 memset(kq, 0, sizeof(*kq));
152
153 kq->kq_func = func;
154 kq->kq_arg = arg;
155
156 SIMPLEQ_INSERT_TAIL(&kthread_q, kq, kq_q);
157 }
158
159 void
160 kthread_run_deferred_queue(void)
161 {
162 struct kthread_q *kq;
163
164 /* No longer need to defer kthread creation. */
165 kthread_create_now = 1;
166
167 while ((kq = SIMPLEQ_FIRST(&kthread_q)) != NULL) {
168 SIMPLEQ_REMOVE_HEAD(&kthread_q, kq_q);
169 (*kq->kq_func)(kq->kq_arg);
170 free(kq, M_TEMP);
171 }
172 }
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